Description

Inside a Grid row set to Auto, horizontal CollectionView with ObservableCollection source is too tall if there is a delay in loading the source. Android does not have this issue.

In the repro project a 3 second delay was added to population of the ObservableCollection.

 public async Task LoadData()
  {
      await Task.Delay(3000);
      for (int i = 0; i < 10; i++)
      {
          Items.Add(new Item
          {
              Name = $"Item {i}",
              Description = $"This is the description for item {i}."
          });
      }
  }

iOS no delay	iOS with delay

Android no delay	Android with delay

Steps to Reproduce

1.) Run repro app and see tall CollectionView despite Grid set to Auto
2.) Remove Task.Delay line in DataService.cs and re-run, see correctly sized view

Expected:
To match Android behavior, iOS CollectionView is correctly sized when the ItemSource finishes populating, even if the screen has already appeared

Actual:
If CollectionView loads source after the screen has appeared, it does not correctly resize itself and takes up excessive vertical space on the screen, ignoring Grid settings.

Link to public reproduction project repository

https://github.com/veronica-aubry/CollectionViewHeight

Version with bug

10.0.40

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

iOS 26

Did you find any workaround?

Manually setting a MaximumHeight or HeightRequest on the CollectionView works, but we would like to be compliant with the WCAG guidelines for accommodating 200% text zoom and hardcoded heights are not good for this

Relevant log output