I have posts and comments on Hexbear from 4 hrs ago that don’t show up

I have a comment on Lemmygrad from 4 hrs ago that doesn’t show up

A recent series of posts from ml to other instances have almost no interaction locally. When viewed remotely, they have higher vote counts (no more comments to compare).

I haven’t extensively looked at the new feed to see if posts are outright missing, but I see the same general pattern spot checking posts that do appear: vote totals much lower than elsewhere, missing comments

I don’t see issues reported on https://phiresky.github.io/lemmy-federation-state/site

Hmm, yeah, the post I linked above is still missing some 50 comments, and most of the post and comment upvotes. Kind of interesting though that it acquired 92/148 comments (at time of writing), before you pushed the fix yesterday it had 2 upvotes and 0 comments. Guess the upvotes are just what has been added since then.
Would be nice if there was a contingency option for server admins for situations like this, no? Something like “Resynch federation events from <timestamp> to <timestamp>”, maybe limitable to certain instances/communities/posts. Not sure if that’s possible with how the federation works currently, but if it is it would be a good feature I guess.
Normally Lemmy returns an error if activities cant be handled (eg instance is down). Then the sending instance keeps retrying until it is successful. But in this case its a bit different, and the sending looked successful.
Anyway I made a change to the federation library to add
Hostheader automatically if missing, then this problem wont happen anymore in the future.Yeah I got that. But couldn’t you (theoretically) add a “resend activities from <timeframe>” option to the API? So you can ask other servers for things you missed. I mean what happened here is one problem where that may be useful, but another would be something like having to restore from day old backups, being a new instance with no history, a network outage, or missing things for whatever other reason.
Like I said I don’t know the data structures involved, but in my layperson head it sounds possible, although you may have to throttle it to prevent abuse I guess.