Exactly same issue here, very annoying, and it's not only in Outlook. If you are using Timemachine, you are in luck: you can restore FF to an earlier version, for me 115.0.2 (as this was before I went on holidays). You lose your profile and bookmarks, but that's easily restored by synchronising with your FF account (if you have one) or from another browser, apart from some settings and managed cookies. When you fire up FF first time, do it without any internet connection and then untick the automated update, that lets you keep the older version. At least until those hiccups are resolved...
