I noticed that when I get a notification about a reply in a Study Group thread, it seems to disappear from my inbox the moment I reopen it. I didn't think this was a big deal, but then another user mentioned they didn't receive any at all. That could partially explain the low activity in groups. Probably worth looking into.
Update: Looks like the latest notification disappeared only after I opened it. Still a bit weird to automatically get deleted like that. Is this the intended behaviour?
Small update: I have a lead on the issue (finally) - it's not resolved yet, but I can see where the error is occurring. Adding a bit more logging, but it'll take someone else responding to one of the messages in Manager Central to let me check it out.
That sounds like it's only accessible to managers, so I can't help you there. Assuming we're talking about the same bug, it should be the same for members and helpers. A helper told me they don't receive notifications when someone posts on a topic, even though they're "subscribed" to it.
I can only speak for my own bug, which isn't that I don't get any notifications, just that they get auto-deleted.
Update: I got access. Is the message from Shamugan good enough for debugging, or do you need anything else?