Can't change the size of a MapView [Xamarin] - ios

Question

I have a MapView in my custom ViewRenderer. I am trying to set it's size like this:
public CustomMapRenderer()
{
var camera = CameraPosition.FromCamera(47.497913, 19.040236, 15);
mapView = new MapView(new CGRect(0, 0, 414, 200), camera); //also tried with this: mapView = MapView.FromCamera(new CGRect(0, 0, 414, 200), camera);
this.AddSubview(mapView);
...
}
The view seems to remain in fullscreen though (414*896), if I check it in the debugger though. Since I found not much documentation, I am asking wheter I am setting it correctly? If so, is that a bug? How should I change the size of the view?
EDIT: Added the relevant XAML code too
The XAML where the Map is embedded in is:
<?xml version="1.0" encoding="UTF-8"?>
<attractionbase:AttractionContentListItemBase xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:attractionbase="clr-namespace:AppTourism.CardView.ItemTypes.AttractionPage"
xmlns:map="clr-namespace:AppTourism.MapModule"
mc:Ignorable="d"
x:Class="AppTourism.CardView.ItemTypes.AttractionPage.AddressWithMapContentListItem">
<Frame
HasShadow="False"
Padding="0"
Margin="{Binding MainFrameMargin}"
RelativeLayout.XConstraint="{ConstraintExpression Type=Constant,Property=X,Constant=0}"
RelativeLayout.YConstraint="{ConstraintExpression Type=Constant,Property=Y,Constant=0}"
RelativeLayout.WidthConstraint="{ConstraintExpression Type=RelativeToParent,Property=Width}">
<StackLayout Orientation="Vertical" Spacing="0" Margin="0" >
<StackLayout Orientation="Vertical" Margin="10" >
<StackLayout Orientation="Horizontal">
<Image Source="iMarkerSmall.png" HeightRequest="30"></Image>
<Label Text="{Binding Pin.Address}" FontSize="Medium" TextColor="Black"></Label>
</StackLayout>
<Frame Padding="0" HeightRequest="100" CornerRadius="20" HasShadow="False">
<Frame.GestureRecognizers>
<TapGestureRecognizer Tapped="Map_Tapped"></TapGestureRecognizer>
</Frame.GestureRecognizers>
<AbsoluteLayout>
<map:CustomMap x:Name="Map" IsEnabled="False"
AbsoluteLayout.LayoutBounds="0,0,1,1" AbsoluteLayout.LayoutFlags="All" />
<Label Text="N/A" FontSize="Medium" FontAttributes="Bold" TextColor="Black" Margin="5,0" VerticalOptions="Center" x:Name="NALabel" IsVisible="False"
AbsoluteLayout.LayoutBounds="0.5,0.5,AutoSize,AutoSize" AbsoluteLayout.LayoutFlags="PositionProportional" ></Label>
</AbsoluteLayout>
</Frame>
</StackLayout>
<BoxView HeightRequest="{Binding SEPARATOR_HEIGHT}" Margin="{Binding SeparatorMargin}">
<BoxView.BackgroundColor>
<Color>#e6e6e6</Color>
</BoxView.BackgroundColor>
</BoxView>
</StackLayout>
</Frame>
</attractionbase:AttractionContentListItemBase>