UIKit.UIImage initWithContentsOfFile Xamarin.iOS - Unreliably throwing exception - ios

Question

Please consider the following error message:
Could not initialize an instance of the type 'UIKit.UIImage": the native 'initWithContentsOfFile:' method returned nil.
I am attempting to load a page on a Xamarin PCL project, and every once in a while, this exception is thrown on iOS. All Android tests seem absolutely fine.
Now when I say "every once in a while" I mean, perhaps once in every 20. I can see no pattern to it whatsoever. It only appears to be happening on an iPhone 5S, however due to the unrepeatable nature of the bug and with limited physical devices to test with I can't guarantee that this is the case.
I can confirm that this is not a case of me setting an icon on a tabbed page as per this SO post, so please don't mark this as a duplicate (unless of course you find another question)
All suggestions welcome
Edit - XAML of the page that on load causes the issue
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:Trak="clr-namespace:Trak"
x:Class="Trak.FinishTrak">
<ContentPage.Padding>
<OnPlatform x:TypeArguments="Thickness">
<OnPlatform.iOS>0,20,0,0</OnPlatform.iOS>
<OnPlatform.Android>0,0,0,0</OnPlatform.Android>
</OnPlatform>
</ContentPage.Padding>
<ContentPage.BindingContext>
<Trak:TrackingPageScaling />
</ContentPage.BindingContext>
<ContentPage.Content>
<RelativeLayout HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
<ScrollView Orientation="Vertical" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"
RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1}"
RelativeLayout.WidthConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1}"
RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0}"
RelativeLayout.XConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0}">
<StackLayout Padding="0" Orientation="Vertical" VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand">
<!-- EVENT/TRAK CONTROL BAR -->
<StackLayout Orientation="Horizontal">
<Label x:Name ="titleLabel" Text="Untitled trak"
FontSize="{Binding FontSmall}"
TextColor="#333333"
HorizontalOptions="StartAndExpand"
VerticalOptions="Center">
<Label.Margin>
<OnPlatform x:TypeArguments="Thickness"
iOS ="10,10,5,0"
Android ="10,15,5,10" />
</Label.Margin>
</Label>
<Image Source="{Trak:ImageResource Trak.Images.edit.png}"
x:Name="editTrakDetails"
HorizontalOptions="End"
VerticalOptions="Center"
HeightRequest="20">
<Image.Margin>
<OnPlatform x:TypeArguments="Thickness"
iOS ="10,5,5,0"
Android ="10,15,15,10" />
</Image.Margin>
</Image>
</StackLayout>
<!-- MAP IMAGE -->
<StackLayout x:Name="imageLayout" Orientation="Horizontal" VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" Margin="0,0,0,0">
<Image Source="{Trak:ImageResource Trak.Images.map.png}" VerticalOptions="Center" HorizontalOptions="FillAndExpand" HeightRequest="180" Margin="0,0,0,0"/>
</StackLayout>
<!-- TOP STATS-->
<StackLayout Orientation="Horizontal" VerticalOptions="Center" HorizontalOptions="FillAndExpand" Margin="10,10,10,10">
<StackLayout Orientation="Vertical" VerticalOptions="Center" HorizontalOptions="FillAndExpand">
<Label x:Name="milesLabel" FontSize="{Binding FontMed}" TextColor="#333333" FontAttributes="Bold" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,0,0,0"/>
<Label Text="MILES" FontSize="{Binding FontXXSmall}" TextColor="#999999" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,-10,0,0" />
</StackLayout>
<StackLayout Orientation="Vertical" VerticalOptions="Center" HorizontalOptions="FillAndExpand">
<Label x:Name="avrgMPHLabel" FontSize="{Binding FontMed}" TextColor="#333333" FontAttributes="Bold" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,0,0,0"/>
<Label Text="AVG MPH" FontSize="{Binding FontXXSmall}" TextColor="#999999" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,-10,0,0"/>
</StackLayout>
<StackLayout Orientation="Vertical" VerticalOptions="Center" HorizontalOptions="FillAndExpand">
<Label x:Name="minutesLabel" FontSize="{Binding FontMed}" TextColor="#333333" FontAttributes="Bold" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,0,0,0"/>
<Label Text="MINUTES" FontSize="{Binding FontXXSmall}" TextColor="#999999" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,-10,0,0"/>
</StackLayout>
</StackLayout>
<!-- DIVIDER -->
<BoxView Color="#DCDCDC" HeightRequest="1" Margin="0"
VerticalOptions="Center" HorizontalOptions="FillAndExpand"></BoxView>
<!-- BOTTOM STATS -->
<StackLayout Orientation="Horizontal" VerticalOptions="Center" HorizontalOptions="FillAndExpand" Margin="10,10,10,10">
<StackLayout Orientation="Vertical" VerticalOptions="Center" HorizontalOptions="FillAndExpand">
<Label x:Name="caloriesLabel" FontSize="{Binding FontMed}" TextColor="#333333" FontAttributes="Bold" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,0,0,0"/>
<Label Text="CALORIES" FontSize="{Binding FontXXSmall}" TextColor="#999999" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,-10,0,0" />
</StackLayout>
<StackLayout Orientation="Vertical" VerticalOptions="Center" HorizontalOptions="FillAndExpand">
<Label x:Name ="elevationLabel" FontSize="{Binding FontMed}" TextColor="#333333" FontAttributes="Bold" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,0,0,0"/>
<Label Text="ELEVATION" FontSize="{Binding FontXXSmall}" TextColor="#999999" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,-10,0,0"/>
</StackLayout>
<StackLayout Orientation="Vertical" VerticalOptions="Center" HorizontalOptions="FillAndExpand">
<Label x:Name ="HRLabel" FontSize="{Binding FontMed}" TextColor="#333333" FontAttributes="Bold" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,0,0,0"/>
<Label Text="AVERAGE HR" FontSize="{Binding FontXXSmall}" TextColor="#999999" VerticalOptions="Center" HorizontalOptions="Center" Margin="0,-10,0,0"/>
</StackLayout>
</StackLayout>
<!-- DIVIDER -->
<BoxView Color="#DCDCDC" HeightRequest="1" Margin="0"
VerticalOptions="Center" HorizontalOptions="FillAndExpand"></BoxView>
<StackLayout Orientation="Vertical" VerticalOptions="Center" HorizontalOptions="FillAndExpand" Margin="10,10,10,10">
<Label Text="NOTES:" FontSize="{Binding FontSmall}" TextColor="#333333" />
<Label x:Name="trakNOTES" TextColor="#333333" FontSize="{Binding FontXSmall}">
Use this space to add any notes about your Trak. It mabe used to add weather condidtions, nutrition, road surface etc. You can also use the icons below to quickly add weather conditions or road surfaces. More icons will be added in time.
</Label>
</StackLayout>
<!-- WEATHER AND TERRAIN TOGGLE ICONS -->
<StackLayout Orientation="Horizontal" VerticalOptions="Center" HorizontalOptions="FillAndExpand" Margin="10,10,10,20">
<Image Source="{Trak:ImageResource Trak.Images.MeIcons.sun-grey.png}" x:Name="sunButton" WidthRequest="50" HeightRequest="50" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" />
<Image Source="{Trak:ImageResource Trak.Images.MeIcons.rain-grey.png}" x:Name="rainButton" WidthRequest="50" HeightRequest="50" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" />
<Image Source="{Trak:ImageResource Trak.Images.MeIcons.cloudy-grey.png}" x:Name="cloudButton" WidthRequest="50" HeightRequest="50" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" />
<Image Source="{Trak:ImageResource Trak.Images.MeIcons.road-grey.png}" x:Name="roadButton" WidthRequest="50" HeightRequest="50" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" />
<Image Source="{Trak:ImageResource Trak.Images.MeIcons.trail-grey.png}" x:Name="trailButton" WidthRequest="50" HeightRequest="50" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" />
</StackLayout>
<!-- SAVE TRAK BUTTON-->
<Button Text="Save" x:Name="saveButton"
Clicked="OnSaveButtonClick"
BackgroundColor="#ffffff"
FontSize="14" TextColor="#037ade"
BorderWidth="2" BorderColor="#037ade"
Grid.Row="11" Grid.Column="1"
VerticalOptions="Center" HorizontalOptions="Center"
WidthRequest="200" HeightRequest="50"
Margin="0,5,0,25"/>
</StackLayout>
</ScrollView>
<StackLayout x:Name="editTrakModalShadow" BackgroundColor="#000000" Opacity="0" IsVisible="false" Padding="5"
HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand"
RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=1}"
RelativeLayout.WidthConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=1}"
RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0}"
RelativeLayout.XConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0}" />
<!-- MODEL TO SAVE TRAK INFO -->
<StackLayout x:Name="saveTrakModal" BackgroundColor="#FFFFFF" Opacity="0" IsVisible="false"
RelativeLayout.WidthConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0.8}"
RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent, Property=Height, Factor=0.1}"
RelativeLayout.XConstraint="{ConstraintExpression Type=RelativeToParent, Property=Width, Factor=0.1}">
<!-- TITLE INPUT -->
<Label Text="TITLE:" TextColor="#333333" HorizontalTextAlignment="Start" HeightRequest="20" Margin="20,40,20,5"/>
<Entry x:Name="trakTitle" Placeholder="Enter file name" HorizontalOptions="FillAndExpand" HeightRequest="50" Margin="20,5,20,5"/>
<!-- DETAILS INPUT -->
<Label Text="NOTES:" TextColor="#333333" HorizontalTextAlignment="Start" HeightRequest="20" Margin="20,40,20,5"/>
<Editor x:Name="trakNotes" HorizontalOptions="FillAndExpand" HeightRequest="100" Margin="20,5,20,5"/>
<!-- SAVE TRAK -->
<Button x:Name="saveTrakButton" Text="UPDATE" Clicked="saveTrakModelButton" BackgroundColor="#ffffff"
FontSize="14" TextColor="#037ade"
BorderWidth="2" BorderColor="#037ade" Margin="20,5,20,5"/>
<!-- CANCEL -->
<Button Text="CANCEL" Clicked="closeTrakModel" BackgroundColor="#ffffff"
FontSize="14" TextColor="#ff6961"
BorderWidth="2" BorderColor="#ff6961"
Margin="20,5,20,30"/>
</StackLayout>
</RelativeLayout>
</ContentPage.Content>
</ContentPage>