Some posts do not have any reply-to information despite being valid replies.
example: https://shigusegubu.club/notice/9iX9QvyWa9ii7nErxY
There doesn't seem to be any noticeable pattern when this happens. Some rare replies just appear to be non-replies, most replies work correctly. There was one pattern once that feld's posts were all without reply indicators consistently, but could be a coincidence.
Could be a problem with my instance, but I'm not entirely sure, so I'll leave it here.