Calendar month names are not always visible

[TomEdwardsEnscape]

Describe the bug
It's possible to use CalendarDatePicker in such a way that the month names in the year view are not generated. The control displays blank tiles instead.

To Reproduce

1. Start the Control Gallery and navigate to the CalendarDatePicker tab
2. Open the calendar pop-up on any of the controls inside the tab
3. Click on the current year, at the top of the pop-up
4. Click outside the pop-up so that it closes
5. Re-open the pop-up
6. Click on the current year again

You will see this:

Expected behavior
Month names should always be visible in the year view, like this:

Desktop (please complete the following information):

• OS: Windows
• Version 11 preview 1

[rabbitism]

Through devtool I can see the text value is already assigned.
And it works fine if compositor is disabled. seems to be a regression.