Out of Sync Items - but won’t show in window

I have some out of sync items as below:

but when I click the link to view it, I can see nothing as below:

How long have you tried waiting for the items to load? Sometimes, this make take a while. However, if they still don’t load even if a long time has passed, then it’s likely some kind of a bug. It’s a known issue, but as far as I know, it’s been impossible to reproduce it at will so far.

I waited about 30 seconds. This error isn’t appearing every time, but if it’s occurred, will continue a long time.