Anyone know why this happens? (Screenshot attached) My library is already synced; this happens entirely at random once in a while. It's annoying because it takes about an hour plugged in and on Wifi for it to fix itself, and iCloud Photo Library won't sync until then.
I haven't noticed any data loss or library corruption but it's still a bit worrying.

I haven't noticed any data loss or library corruption but it's still a bit worrying.
