I have set Firefox to update automatically when the browser is not running. Every time the Firefox browser updates, my default homepage is changed to "http://www.msn.com/?pc=ACTE". Currently, my homepage is set as "Firefox Home (Default)". I have noticed that if the "Custom URLs..." option is selected, and a custom URL is set, but then changed to the "Firefox Home (Default)" option, the previously entered URL will revert back to "http://www.msn.com/?pc=ACTE" if the "Custom URLs..." option is selected again. I have done multiple malware checks using Malwarebytes, but found no malware. I have done some looking around in about:config, and found two values that weren't added by the browser. I know this because it is impossible to delete values in about:config added by the browser itself. "browser.startup.homepage_override.buildID 20220126154723" and "browser.startup.homepage_override.mstone 96.0.3" are the two values not added by the browser. You can even see (in the attached image) that the two values can be deleted by clicking the trash can icons. However, when trying to delete them, they eventually return. I apologize in advance if this is seen as a duplicate post, but after rigorous research, I have found no post that solves my issue.