The shortcut for RDM is Ctrl+Shift+M and the shortcut to open the Bookmarks Manager is Ctrl+Shift+O, so it sounds that the Logitech mouse settings are configured to these shortcuts when you press these mouse buttons. Back would normally be "Alt+cursor-left" and Forward would be "Alt+cursor-right", so you need to check the mouse driver settings.

Thank you for replying. That is the first thing I thought. I checked my mouse settings, and the back button is set to back only, and the forward button is set to forward only, so I am still looking for what happened in the past few hours that caused this problem. I have also since downloaded the latest version of Firefox (Version 93.0 64-bit) and installed it hoping that might reset some setting that got accidentally changed, but that did not fix the problem.

Maybe also check the settings of the Logitech SetPoint extension that shows in the troubleshooting information.

I am not having the issue with Edge or Chrome, so I will uninstall the mouse software, reinstall it, and see if that solves it. Thank you for your help. I really appreciate it.

Things appear to be working normally again. I did not actually uninstall and reinstall the mouse software. I will keep browsing and see if the problem arises again. I hope it does not, but for now, using my mouse for forward and back works normally.