I have the S20 FE,
One UI Ver. 3.1
Android Ver. 11
Ever since the last update the messages app just pops open every 10 mins or so. It's very annoying. I can't exactly uninstall then reinstall the messages app so I don't know what to do.
I have Note 20 Ultra and this problem appeared after last software update.
Looking in app settings, the Messages app went from being opened 5-10 times a day (when I used it) to 150-170 times a day after the update.
Please find this Samsung!