Xamarin long text binding causes layout cropping - xamarin

Question

I have a layout in a Xamarin Forms app. It consists of a ScrollView containing a StackLayout and various controls down the page. One of the controls near the top is a label with text bound to a string in the view model. Sometimes this is a very long string and in those cases the content gets cropped halfway down the page.
I've discovered that if I modify the layout while debugging the hot reload causes the view to display correctly.
I've also tried replacing the StackLayout with a grid with Auto sizing rows with the same result.
I have also found that if I set a HeightRequest on the label of something like 8000 and then set to -1 after the binding is updated it sometimes (not always) sizes correctly.
Does anyone have a suggestion on what I can try next?
Layout is essentially:
<ScrollView>
<StackLayout Orientation="Vertical">
<Label Text="Header" />
<Label Text="{Binding PotentiallyLongText}" />
<Label Text="Paragraph of text" />
<Label Text="Another section of text" />
<Label Text="Another section of text" />
<Label Text="Another section of text" />
<Label Text="Another section of text" />
</StackLayout>
</ScrollView>
When the PotentiallyLongText is a very long paragraph with line breaks the content wil end abruptly (often cropped mid-line) further down the page. The ScrollView however does scroll to what would be the correct height.
Here's a screenshot of how it looks when I first load the page:
(The PotentiallyLongText label is the text with the white background)
And if I leave the app and come back or even hot reload via the debugger it looks like this (as it should)
What could cause the layout to cut off initially?

Answer 1

There is a LineBreakMode property of Lable, you could set LineBreakMode="WordWrap" to check.
Have a try with following code to check:
<ScrollView>
<StackLayout Orientation="Vertical">
<Label Text="Header" />
<Label Text="{Binding PotentiallyLongText}" LineBreakMode="WordWrap"/>
<Label Text="Paragraph of text" />
<Label Text="Another section of text" />
<Label Text="Another section of text" />
<Label Text="Another section of text" />
<Label Text="Another section of text" />
</StackLayout>
</ScrollView>

Answer 2

I have seen this bug in Xamarin.Forms 5.0.0.2012 and reported it on GitHub.
I downgraded to Xamarin.Forms 4.8.0.1821 and it worked.