UIPickerView Display Bug: everything is very dark - ios

Question

UPDATE: I solved this using a workaround with custom views on the picker instead of strings. Still really curious why this was happening though.
Only two of our users reported this bug and so far and it's pretty strange. I am unable to replicate it on the sim or any of our test devices. Basically, for this one user, a UIPickerView displays everything very dark. Here is an image of how it's supposed to look:
Here is what it looks like on the user's phone who reported the bug:
At first glance, the bugged pickerview appears black. But if you turn up your screen brightness all the way and look really closely, you'll see that the picker view is actually there (also, the textview wouldn't have populated if it wasn't there). The picker view is displaying with an almost black background and black text.
I'm not doing anything tricky or messing with the frame of the picker view to create it or manage it:
- (UIPickerView *)pickerView
{
if (!_pickerView) {
_pickerView = [[UIPickerView alloc] init];
_pickerView.delegate = self;
_pickerView.dataSource = self;
}
return _pickerView;
}
I'm not using any custom views, just assigning strings in pickerView:titleForRow:forComponent
#pragma mark picker datasource
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return self.rowTitlesForComponent.count;
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
return ((NSArray *)self.rowTitlesForComponent[component]).count;
}
#pragma mark - picker delegate
- (NSString *)pickerView:(UIPickerView *)pickerView
titleForRow:(NSInteger)row
forComponent:(NSInteger)component
{
return self.rowTitlesForComponent[component][row];
}
Here's my hunch: I'm assigning the picker view to the input view of the textfield so that it pops up as a "keyboard":
self.textField.inputView = self.pickerView;
The textview is a subview of a custom tableview cell. This custom tableview cell is a subclass of another type of tableview cell that contains textviews which pop up ordinary uikeyboards. In this superclass, I'm assigning the keyboard appearance to UIKeyboardAppearanceDark. The odd thing is that this is affecting <1% of our users, so perhaps it's some off combination of OS version and code or something?
I tried messing around with all the accessibility settings on the phone, but could not replicate.
Do you have any idea what might cause this?