I really don't know if I'm the only one who has this but this has been getting on my nerves ever since I joined 3 years ago
Everytime I get a PM, it sends me the "x has replied to a personal conversation" twice
Example:
I honestly don't see a need of getting a notification if I get a pm at all, I already get an inbox notification, so it doesnt make any sense to get an additional 2 notifications.