XF 1.5 Issue With Notifications on Watched Threads

[aeriverse]

Several of my users have been coming to me with the complaint that when they watch threads, they don't receive notifications for them. They'll still get notifications for other watched threads, but there's ones in particular (with no specific pattern) that never alert them to new posts. How can I solve this issue?

 

[Floyd R Turbo]

Alerts or emails, or both?

Are they not getting any notification, or are they expecting notifications for replies that happen subsequent to the first since they viewed the thread?

Are they expecting functionality like vB where they got notified for threads that haven't been read even though they visited the site? In vB, it resets all notifications upon just logging in, in XF, you have to look at the actual thread replies to reset the alert/email notification.