My browser (latest nightly) thinks its a word processor. Enter key in Google search drops to a new line

My Firefox browser (nightly snap 154.0a1 on Ubuntu 24.04) has been misbehaving lately (~2 weeks now) and I'm at a loss why. First, when I scroll using the mouse wheel, the scrollbar continuously shoots back to the top constantly during scrolling. Second, when I type text in a Google box and hit enter key, it drops to the next line - like one would expect in a text processing application. Third, when on YouTube, trying to rewind/forward video instead starts navigating to clickable links. Of particular note (see the attached screenshots) is the appearance of text (such as "Skip navigation" and "Volume" to name a few) - something I've never seen before. This happens with a new profile as well. Now, I know that nightly will sometimes have broken items but this is a weird one. I at one time thought the batteries on my wireless keyboard could be responsible but new batteries (confirmed new with a digital multimeter) did not change that. I'm on Ubuntu 24.04 LTS fully patched. Anyone here with ideas on what it might be?