Sometimes BPM notifications are only showing up in Administrative tasks and not My Tasks

Users are reporting intermittent issue where they are not able to see the approval notification in BPM worklist My Tasks. But the same notification is shows up when they check in Administrative tasks. As I said this is again happening intermittently to different users. Want to know if anyone has noticed this issue and what can be done to resolve it. This is the 3 user who has reported similar issue in the past 1 month