This is fixed in the latest Alpha. Just wait, it'll resolve.

Ahh... I remember that it was an issue back in 2017-2018, but you had to send something into the same channel to clear it. But I assumed that it was fixed since it has been like 3 or 2 years since I last experienced it

I just got this issue for the first time, a number 2 is stuck on one of the servers I'm apart of.

This has only started happening today and even left the beta program on the play store to see if that resolves it but basically, when I go to read an unread channel or a ping, they remain there even after I've moved to another channel or a different Discord. The only way they disappear is even I clear the 'xxx messages since you last read' banner in each channel.

Unread/Ping notifications stuck on even after reading?