TabViewItem header hit test/mouse over problems in 1.6.0 experimental 2

[DHancock]

Describe the bug

The hit test and mouse over areas for tab view item headers and their buttons are incorrect. Please see the attached video.
The bug is only evident when there is an even number of tabs and the display scaling is set to 125%. It isn't reproducible at 100% scaling, I haven't tried other scale factors.

Screen.Recording.2024-07-05.153239.mp4

Steps to reproduce the bug

1. Build the attached solution.
2. Set display scale to 125%.
3. Open an even number of tabs.

HitTestIssue.zip

Expected behavior

No response

Screenshots

No response

NuGet package version

WinUI 3 - Windows App SDK 1.6 Experimental 2: 1.6.240701003-experimental2

Windows version

Windows 11 (22H2): Build 22621

Additional context

I also experienced similar bugs in my real app in the tab's contents, not just the tab item headers. For example the expander drop down buttons could be clicked when the mouse was outside of any part of it's expender. I suspect it's a common cause.