Can't see comment replies

Hey all. I'm having this issue where a bunch of content replies disappear on me. Or, rather, they are in my inbox, but when I click them to go reply and vote on them in the comments of the post where they are, they are completely missing from the thread/conversation. So to make it clear, they never disappear from my inbox, but they just can't be seen in the comments section itself, under the associated post.

Is this a bug or expected behavior?

Thanks for any help.