Not super clear where to find what, link to live, also why your script is inside the content embed which is for embedding external html coming from 3rd party
I recall at one point we had an issue with dom content event not getting called on dynamic pages. I'll start a test there to see if that was addressed. thought it was
@AdamOBryn can you drop a console log first thing in there to see if that prints? I'd also log one of the elements and lastly a log in the event listener
i wonder if any of the custom head code is messing with it. possibly that head code is only allowed to run on your domains so its not impacting my clone?