Dear commenters - it appears that your instance is not federating outwards. That is, it appears to be unable to send messages to other instance inboxes. (Verified with both tucson.social and beehaw.org)
I do see your comments on your main instance, but I cannot reply to them from beehaw or tucson.social - I can however make new posts in the thread without issue.
I encourage y'all to reach out to your Admin and have them check that federation activity hasn't been accidentally blocked on outbound connections. This can be verified with a cursory glance at the lemmy logs, and will show that any external address is unreachable - either blocked or DNS is unresolvable. Most of these issues can be resolved with a docker daemon restart and sometimes a firewall restart (before the docker daemon restart).
EDIT: NEVERMIND - The missing comments seem to be stemming from the fact that the instance the user is posting from is blocked on beehaw.org (and consequently tucson.social since we share blocklists).
I'm gonna re-review my blocking of some of these more general instances like I did with lemmy.world.