Description

Shell.NavBarIsVisible="False" set on ContentPage always worked but after upgrading to .NET 9 from 8, the navigation bar appears and disappears which create a flickering. It only happens quickly, and it was hard to figure out what it was initially. It doesn't happen when revisiting the page again. I only worked out what was happening from screen recording the app on iPhone and reviewed it at a slow speed. Happens only on iOS.

I've tested with a clean project with sample data and the same issue was confirmed. I only tested with Shell tab bar navigation.

Steps to Reproduce

1. Create a MAUI project
2. Add TabBar navigation
3. In any page, add Shell.NavBarIsVisible="False"
4. Build the app
5. Switch tab pages on iPhone

Link to public reproduction project repository

https://github.com/toshimitsu-o/MauiSampleDotNet9

Version with bug

9.0.0 GA

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI

Last version that worked well

8.0.100 SR10

Affected platforms

iOS

Affected platform versions

iOS 18.1

Did you find any workaround?

Adding Shell.NavBarIsVisible="False" in AppShell.xaml didn't work but creating custom shell renderer worked as described in the link below.
#18948 (comment)

Relevant log output