@melunaka I got the same on octodon.social but it was only happening on very specific toots and I couldn't find a specific pattern 
@Eramdam Apparently I can go to other «parts» of thread which are weirdly not connected to each other, by searching for them manually on a user profile, and I have the same problem with them.
@Eramdam It seems I can’t see the first toots of the thread on my instance, so that may be related.
e.g. I can see publicly https://catboy.cafe/@bram/100271016511645076 on the static website but not in the logged-in interface…