@Dimitrios-Kanellopoulos
I got a collection of Zombie notifications on my S9 (latest fw), Android SA - beta, LG G6 Android Oreo. So, here are just my two cents:
when someone accepts Google Calendar invite it is impossible to remove that notification. I use Google calendar all the time, and when I invite someone to the calendar event, and they accept, there is no way to remove that notification.
declined calls stay for no reason, even if I check the notification
a bug - If I get a notification, for example SMS, and I use quick reply - reply from notification, when I press send the watch beeps for new notification but it was not a new notification, just a reply to the current one.
https://images.techhive.com/images/article/2016/08/quick-reply-nougat-100678494-orig.jpeg
^just to make sure everyone understands what I think of when I say quick reply.
If I find more stuff I’ll write it here.
Cheers