Navigation KeyEvents consumed when there is nothing to navigate, bug?

[Michael Strauß]

Just to add a data point:
I've tried to recreate this scenario in a WinUI 3 application. A
single button, and nowhere to shift focus.
While the button does consume action keys (space and enter), it does
not consume the tab key.
Interestingly, it also doesn't consume the tab key when the focus
_can_ be moved to a different control.