I'm not mad, lol. I apologize if I gave you that impression. The entire situation is just perplexing since I can't replicate any of your issues so I'm not sure what's going wrong.

I don't understand the difference between a "comment post" and a "comment on an activity post"

There's 2 types of streams in CB Activity. Activity and Comments. Notifications in the Comments section apply to all Comment streams. Activity streams use Comment streams for their commenting.

The Comment notification under the Activity section is just to enable a notification strictly for activity comments. There isn't a comment reply notification strictly for activity. You can have enable comment reply notifications globally, which applies to all comment streams including Activity comment streams, under the Comments section if you want comment reply notifications. I'll review adding a parameter for comment replies exclusively for activity posts in a future release.

If CB Activity > Notifications > Comments > Replies is not sending notifications for replies to comments for you then that's a different issue. If possible can we please focus this topic on a single problem at a time as it's getting too hard to follow. Lets make 1 notification, that isn't working, working again.

I should also mention that comments on your own posts will not send notifications. So if you're testing this with a single user that maybe why you're not seeing a notification be sent. So for example if User A makes an activity post then User A comments on that activity post it won't send a notification.

Success! Was able to finally track down the cause. There was a parameter mixup. If you didn't have group activity AND group gallery notifications enabled it would fail. This is now fixed in latest build release. I've already installed the new build release for you and confirmed working to send group post notifications. If you've any further issues with other notifications please create a new topic per notification so we can track these issues better.

As for why a notification seams like it's sending to the wrong amount of users it's because you've a ton of deleted users on your site. Specifically in groups you've users that no longer exists. CB Activity doesn't check for this. It's simply accepting a list of user ids in the _groupjive_users table for a group and sending a notification to those ids. For example your "Practical Medicine" group has 4 valid users that exist, but it actually has 12. You can see these missing users in CB GroupJive > Users as their User column will be empty.

Deleting a user should delete them from CB GroupJive, but if you set "Auto Delete" to "Disable" in CB GroupJive > Parameters > General that won't be the case. No there isn't a tool to clear all this out. You'll need to do that yourself.