The update should work now with your extension (in multiple browsers)! As for notifying the devs: they'll probably just view it as this is expected behavior when the DOM is rapidly mutating which is what was happening. The silver lining here is I got to work with a neat extension that I actually find somewhat useful!
It works now - thank you!!
Thanks again for letting me know! I really appreciate the support, and it's really satisfying squashing bugs (not in real life tho)