I just checked the github page and it seems this bug is low priority:
Memmy does sometimes not let you post or comment due to a weird bug that thinks you‘re posting in the wrong language.
I just want to point out that I‘ve had this bug twice so far and others (maybe many) will have it too which severely hinders the growth of lemmy at this critical time.
If someone reads this who has any clout, stuff like this is what can trip a promising platform like this. Exponential growth and all.
Have a good one.
In my experience it's not a lemmy problem, it's a kbin problem. Typically it happens when replying to kbin comments, even if the post is on lemmy. I find that even when you set the language to post your comment, any subsequent replies from kbin won't come back to lemmy.
The issue is most likely to do with how kbin federates with lemmy. Our stuff makes it there, but their stuff doesn't always make it to us.
If that’s really the case it would be worth getting in touch with the developers of Kbin (and ofc Lemmy).
/u/sunaurus@lemm.ee is on it.
Great