I posted this thread on jlai.lu. I got no replies as far as I could see from sopuli -- no notifications, and when I enter that thread there are still zero replies. But when I visit the thread on the hosting instance, I see a reply. This behavior is the same as if I were blocking that community -- but I am not.
When I search in sopuli for the direct link to the comment, the search finds it. And then I was able to forcibly interact with the comment.
I have to wonder how often someone replies to me and I have no idea because the response is hidden from me. This is a serious bug. Wholly unacceptable for a platform designed specifically for communication.
update 1 (another occurrence)
Here’s another thread with the same issue. Zero replies when I visit that thread mirror within sopuli, but 3 replies when visiting direct. I was disappointed that high-effort post got no replies. Now 2 months later I see there actually were replies. I will search those comment URLs perhaps in a couple days to interact. But I’ll hold off in case someone wants to investigate (because I think the act of searching those URLs results in copying the comments which could interfere with the investigation).
update 2 (subscription relevancy)
I was asked if I am subscribed to the community. Good question! The answer is no, so there’s a clue. Perhaps mentions do not trigger notifications if no one on the instance of the mentioned account is subscribed to the community. This could be the root cause of the bug.
#LemmyBug