Plugins cannot be opened by Final Cut in the ”Motion Title” format any more

[Daniel Nauroth]

Yep, you are spot on, Ben.
It was the search field.
The 4K and HDR search was the cause.
I had contacted apple today, and it took us almost 10 min. to find the problem, but indeed it was the search field.
Thanks so much for helping me as well, Ben!
Have a great day!

[Brie Clayton]

Thank you for solving this, Ben!

[Ben Balser]

This is a super common mistake by both beginners and seasoned FCPX pros. Apple seriously needs to do something to either make entries into the search more obvious, or auto-clear the search field after the search is done. I chalk it up to bad GUI design.