Issue was reported to "google dev team" but they claimed issue not existing even sooo many users report the same. Every time I post my Samsung phone specifications, sw version and app version they marked post as "offtopic". I recently swapped my S10 for S10+ with all up to date software but issue is still present. Link to google support :
For the long time now, I've been getting continual notifications from my Android Gmail app, even when I am trying to read the email that it is notifying me about. When I open the Gmail app, it clears the notification (as it should), but then when I open one of the unread emails, it suddenly pops up the notification again, listing all of the still unread emails. This is not notifying me of *new* emails, just re-notifying me of emails I have already received. Here is an example: Let's say I have 4 unread emails in the notification. I open the app, and the notifications go away. As soon as I open the first unread email, it pops up a notification that I have 3 unread emails. Very annoying, but then I go and open the next unread email, and it pops up another notification that I have 2 unread emails. Same thing when I open the next. It doesn't stop notifying until all emails are actually read. And here is something even more annoying. Let's say I open an unread email, and it marks it as read, but I decide I want to change it back to unread. Then it immediately notifies me that I have an unread email, and it keeps on notifying me. I just want to mark it unread so I can follow up on it later. Up until a few months ago, everything worked the way I wanted it to. I got notifications only when I got NEW unread email. And that's the way it should work. Or at least, you should be able to configure it to work that way. I have searched through the settings but have been unable to find anything that lets me change the behavior of the app notifications. If anyone has a solution, please let me know.
Colegue have S20 and experiencing the same. Dont think will move to any new Samsung untill its sorted. As per them buy a Google Pixel if you want things working fine 🤦♂️
Thanks for reply, already using two gmail and one exchange. Tried with one only than with two on it and alltogether....no joy !
Unfortunatelly other XX replys/users on google support have the same with different models/android versions/accounts