Big Sur - Unable to remove login items
I recently upgraded to Big Sur from Catalina. Since upgrading, I've had a few login items in system preferences that I no longer use. I have tried many times to delete them from Preferences/Users & Groups/Login Items. They delete OK, but when I reboot they are back again. I have tried deleting the /Library/Preferences/Loginwindow.plist and ~/Library/Preferences/Loginwindow.plist, but every time I reboot they re-appear with the same list of login items.
Any suggestions?
Mac mini, macOS 11.0