I cannot get the full Library from the Photos app to appear in the FCP X Browser

Are you using iCloud Photos Library?

Strange it's not appearing if you aren't. I added an image and didn't have to relaunch for it to appear.

Yes that’s true. Someone else reported it recently. Don’t know if it was a change in Photos that caused this. The app was rebuilt for Catalina as a punishment for our sins.

I have exactly the same issue. My Photos apps and Final Cut Pro X apps are giving me lots of other bugs too. The OS Catalina upgrade is sub-par and Apple should fix them asap.

I have same issue. Seems like significant bug that needs to be fixed.

Which one? That you can’t see all the photos, or that it doesn’t update after relaunching?

Can't see all the photos. Only My Albums and Albums show and those don't update when new photos are added to either and relaunching.

Yes

If you’re using iCloud Photos Library the images have to be stored locally on the drive. They can’t be accessed from the cloud. That’s probably why recent images are not appearing.

I am not using iCloud Photo Library and I am having the same issue with all photos not appearing.

That’s a different thing. iCloud doesn’t effect that. What I was talking about was whether images added to my albums will update in FCP.