I couldn't find a similar issue that has already been resolved, so I figured I'd post mine here.
Yesterday morning, I was looking into the Lightroom Mobile Discover tab when I decided to post some of my photos there. I was only able to post 20 Edits when I could no longer create any new posts. I could go through the configurations, and give them a title, description, and tags, but clicking the check mark only gave me the "Your Edit is Live" pop-up on my preexisting feed. There was no sign of any new post.
I thought that maybe there was a limit to how many posts can be made in a day, so I resolved to try again today. However, upon attempting to test my theory and share another Edit just a few minutes ago, the same issue occurred in which I cannot see any new posts of mine; it just takes me back to the same 20 Edits I've already shared.
If anyone else has faced this issue and found a resolution, I'd be grateful to know the workaround!
Device: iPhone 13 Pro, iOS 15.5 Subcription: Lightroom Mobile Premium
Edit: I just tried again now that 24 hours have gone by and I am able to post my Edits! It seems as if there is a limit of 20 posts per 24 hours (I thought it would reset after midnight, but that was not the case).