Removed by mod

I also see an issue. Compare lemmy.world and lemmy.ml.

In another example it seems that one comment has propagated with time (it was not there when I responded).

I’m not sure who to ping about it

I can see them. Maybe it’s related to language settings. Have you set your languages at https://lemmy.ml/settings ? If yes, try selected Undetermined and see if the posts become visible again.