I seem to get this consistently using the dropdown at the bottom of the list. It just refreshes the list (and limit) being currently displayed.
The top dropdown seems to work fine.

I'm experiencing this same issue at File:Donald Trump mug shot.jpg on enwiki (also see its talk page). The file still has all the description pages.

I've come across this 4 or 5 times in the past day (I'm a checkuser so I do a lot of this stuff). Anyway, the second problem, with autoblocked globally locked and hidden accounts, may be related to a global IP block which is now in place. I have limited opportunities to test this.

My only concern would be ranges which don't adhere to the /64 rule. A notable example is AT&T, for example 2600:387::/32, where users generally hop around within a /48 or larger, and a limited number of /64s are shared. If a filter is being pestered by such an IP hopper, this is going to rapidly propagate throughout the entire usable customer range, causing certain collateral. I've seen other ranges like this, but admittedly there's not many. If this was on enwiki, where we don't currently have any filter blocking enabled, we'd probably sometimes want to exclude these ranges from any blocking filter Saying that, I don't see a checkbox as a particularly useful way of achieving this.

I haven't seen this error in the last couple of days.
I suggest whatever was affecting checkuser has probably been resolved.

I've been getting this intermittently through checkuser since around Thursday afternoon (UTC).