Describe the bug

When opening up the Menu sample the render call at Microsoft.Toolkit.Uwp.SampleApp\Pages\SampleController.xaml.cs 506 fails the first time and works after waiting and opening up the Menu sample a second time. The text that is being rendered is the same on the times that it fails as the times that it succeeds.

failed.txt

This error get logged.
Exception thrown: 'Windows.UI.Xaml.Markup.XamlParseException' in Microsoft.Toolkit.Uwp.SampleApp.exe WinRT information: Unknown parser error: Scanner 2148734242. [Line: 205 Position: 41]

Broke in the split controls merge.

• Is this bug a regression in the toolkit? If so, what toolkit version did you last see it work:

Steps to Reproduce

• Can this be reproduced in the Sample App? (Either in a sample as-is or with new XAML pasted in the editor.) If so, please provide custom XAML or steps to reproduce. If not, let us know why it can't be reproduced (e.g. more complex setup, environment, dependencies, etc...)

Steps to reproduce the behavior:

1. Open Menu sample on sample app.
2. Menu sample does not load.

Expected behavior

A clear and concise description of what you expected to happen.

Screenshots

If applicable, add screenshots to help explain your problem.

Environment

NuGet Package(s): 

Package Version(s): 

Windows 10 Build Number:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] May 2019 Update (18362)
- [ ] May 2020 Update (19041)
- [ ] Insider Build (build number: )

App min and target version:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [ ] October 2018 Update (17763)
- [ ] May 2019 Update (18362)
- [ ] May 2020 Update (19041)
- [ ] Insider Build (xxxxx)

Device form factor:
- [ ] Desktop
- [ ] Xbox
- [ ] Surface Hub
- [ ] IoT

Visual Studio 
- [ ] 2017 (version: )
- [ ] 2019 (version: ) 
- [ ] 2019 Preview (version: )

Additional context

Add any other context about the problem here.