Our little instance often has federation problems. Sometimes they’re obvious, and sometimes more subtle. Sometimes it eventually catches up, but I suspect not always.

I don’t know what causes the problem, as I have no visibility into the systems, and the person (people?) running the instance don’t communicate here. I think you would have better luck investigating by signing up for shell access and asking in the bulletin board there.

For what it’s worth, my recent posts from here to lemmy.world communities seem to be getting through, as they have comments from lemmy.world users. Example 1, Example 2.