tried on desktop edge (114.0.1823.58, amd64-windows, never ran outside InPrivate) and on a fresh install of firefox for android (114.2.0) and the error message is returned both when logged out and logged in on both browsers - either as a toast on a blank page when accessing from a hyperlink or as a full error page when trying to access removed posts directly.
testing was done on https://burggit.moe/modlog/30 -> https://burggit.moe/post/2475 and https://burggit.moe/modlog/123 -> https://burggit.moe/post/28404 [nsfw].
Doing a quick check on changes from 0.17.4 to 0.18, seems like the most probable culpirit are these lines from this commit.
It doesn't look like these changes were intentional either. Seems like the intent was on making deleted/removed posts not visible to non-mods/admins/creators on community post listings, rather than not visible at all.
I've got zero experience with asynchronous rust (or rust, for that matter), but this doesn't seem too hard to change (other than a potential distinction between removed and deleted posts). i'll still need to figure out how to make sure the changes don't break something else in the process, though.