Hello, Anonymous, my solution may seem very general but it may help.
I would type "notifications" to get to the menu on this screenshot and would turn off the annoying notifications of any program.
Another way is to contact the Microsoft Support Team and try to fix the problem from their side.
As you can see, you can face different system issues and bugs, and the only way to feel safe about your significant data is through MO365 backups, don't forget about them and your organization will thank you for it in crisis situations.
