Reported by @Danny_B and independently on huwiki. Seems to have started some time last week.
@daniel could this be caused by T210307: Forcelinkupdate appears to have stopped working (on ENWIKI at least)? The timing doesn't match but maybe people did not notice for a while.
@Tgr No, that error is specific to forced updates that are not edits.
Wikidata and categories use pretty different mechanisms for putting stuff into RC... the only commons factor is the job queue, I think.
Same as T211849 ?