"One view" gumball ghost

In the _OneView view, the gumball cannot be used (it appears a moment when the transition between the views occurs). Disabling the “update plan C” option the gumball is visible.
Edit: I noticed only now that the automatic reset of the Gumball was activated … turning it off the gumball becomes visible and usable again

have you tried not using space navigator? just guessing but maybe that’s the main problem.

Yes, same thing.