I noticed a distinct lack of response to comments and looking at the threads from other instances shows that my comments aren't appearing outside of lemm.ee, and going to the link I shared shows there are 0 up-to-date instances with lemm.ee.
This happened around the big update in December, too. Not sure what the cause is, but here's hoping it can be resolved soon!
*Dunno if this info would be helpful, but the last comment of mine that seems to have federated properly was from 07:15UTC, and the first comment that seems to be missing was from 14:15UTC. So something happened between then.