Multicam angles just completely disappear / go blank

Has anyone got a clue whats going on with my multicam angles just completely disappearing here please? The footage is still there and displays in the main viewer OK. All four angles just go blank at the same specific time. Thanks.
YouTube link here:  (Sorry but I cant get it to embed properly using the Insert YouTube way above)

I've had a different issue with multicams since forever:
fcp.co/forum/4-final-cut-pro-x-fcpx/36776-angle-viewer-bug

Wonder if it's related?
Make sure you use the Feedback to let Apple know! And hopefully Apple will give multicam an overhaul soon...

Wow, thats odd too. Ive never had that one before myself.
TBH I'm thinking of stopping using FCP altogether and moving over to Davinci.
Which I know will come with all of its own problems, but MOST things I tend to use FCP for these days for is just too buggy.

What sorts of trouble-shooting have you tried? Resetting FCP preferences? Deleting generated media? Removing Chrome and its keystone daemons ( chromeisbad.com for info and instructions) then reinstalling FCP? Transcoding that media to ProRes? You could also post the question in the Apple-hosted FCP discussions.

TerryB wrote:

What sorts of trouble-shooting have you tried? Resetting FCP preferences? Deleting generated media? Removing Chrome and its keystone daemons ( chromeisbad.com for info and instructions) then reinstalling FCP? Transcoding that media to ProRes? You could also post the question in the Apple-hosted FCP discussions.

Hi
I've reset FCP.
I've deleted generated media.
I've since reimported into a new library using ONLY the import window (Not drag drop).
Removing Chrome and its keystone daemons ( chromeisbad.com for info and instructions) then reinstalling FCP - Not tried nor do I want to really.
Transcoding to Prores I've not tried yet, but will try in a moment.
Ive not been onto the actual Apple forums yet, but will head there now.
Thanks

Here is the solution:
After importing the clips ADD META DATA to the clips for Camera Angle and Camera Name. Create a new Multicam, sync it automatically. The issue has now completely gone
But then this brings a new problem but I've worked out the solution so I'm adding it here.
With the above solution "Working" there is now another issue. When I add a new angle and then try to alt copy drag the Sony A7S3 clip from one angle into the new angle (I want to use a zoomed version) it screws it up again.
The ONLY solution is as follows. INSIDE the MC make the angle you want to use a compound clip, then alt/copy it to a new angle. If you try to create the compound clip in clips browser section above and then drag it in it screws up the whole multicam again.

Glad you figured it out. Adding names and angles is the standard and recommended way to prep clips before creating multicams. I regularly option drag an existing angle's clip into a new angle to create CUs or alternate framing without needing to first make it a compound. I'd say there's something odd going on with your system or 3rd party plugins or Chrome or an App Cleaner has borked something.