Without more details, it’s hard to know what you are describing. Do you mean comments from other people on posts you make? or your own comments?
I assume you are talking about the main webapp, lemmy-ui, and not a smartphone app or other front-end? The first thing to try is anonymous reading of the same post - are the comments there for incognito mode?
I’ts not uncommon for people on Lemmy to set their languages to something odd and and Lemmy will hide a lot of content.