Unity appears above Flutter when coming from background

[LegendAF]

Describe the bug
On iOS we are seeing an issue in Flutter 3.27 that was not present before. When you come from the background sometimes you can see Unity if you have it hidden behind any Flutter UI. Or any Flutter UI above it will flash.

Screenshots
https://github.com/user-attachments/assets/6b009195-6a1f-4f24-8ae4-cb13b24187c5

Unity (please complete the following information):

• OS: Mac
• Version 2021.3.22f1

Smartphone (please complete the following information):

• Device: iPhone 16 Pro
• OS: iOS 18.3.1

Additional context
Anyone else seeing this? Trying to track it down as it is not an ideal experience for the way we are using FUW. This does not happen on Android. It also happens on Flutter 3.29.

[timbotimbo]

I'll have to look into this, but my first guess is that this is a Flutter platform view or impeller bug.

Flutter testing for regressions with platform views isn't great.
For android I had to create issues in the Flutter repo to prevent it breaking in several releases (3.19, 3.22 and 3.29).

So I would not be surprised at all if thisbis a Flutter regression.

Maybe try 3.27 with impeller disabled to see if it is impeller related. (3.29 won't work as it forces impeller).

[LegendAF]

It's a Flutter impeller issue, filed with Flutter