That beta version got corrupted, so I deleted it and reinstaled folderview from APP tab and now it's working as it should. So deleting and reinstalling should help.
You can see version in my screenshot, I believe that it's beta version. For me it was hiding Nextcloud containers when I installed it first, but later on it stopped working. Maybe try to wait for the next update of the Nextcloud server, if it still works after that.