Apps with a custom background flash a white background for a couple frames on some devices

* .NET Core Version: (e.g. 3.0 Preview1, or daily build number, use `dotnet --info`) 6.0.100
* Windows version: (`winver`) Windows 11 10.0.22000
* Does the bug reproduce also in WPF for .NET Framework 4.8?:
* Is this bug related specifically to tooling in Visual Studio (e.g. XAML Designer, Code editing, etc...)? If yes, please file the issue via the instructions [here](https://docs.microsoft.com/visualstudio/ide/how-to-report-a-problem-with-visual-studio?view=vs-2019).
* Security issues and bugs should be reported privately, learn more via our [responsible disclosure guidelines](https://github.com/dotnet/wpf/blob/main/README.md#reporting-security-issues-and-security-bugs).

**Problem description:**
Apps with a custom background flash a white background for a couple frames on some devices (previously asked Stack overflow to no avail, pointed to likely a software issue)
**Actual behavior:**
Window flashes white before fully loading.
**Expected behavior:**
Window opens with the correct background color instantly
**Minimal repro:**
```
dotnet new wpf
```
edit MainWindow.xaml to have a background attribute
```
dotnet build
```
and run the app.