Embedding multiple videos in a PDF only plays the first, despite all being set to autoplay

I have the following issue and have found no solution so far:

I want to embed multiple mp4 video files inside a PDF file in Acrobat with Rich Media. But doing so only causes the "first" instance of videos to play, which in this case, is a page where 2 smaller videos are embedded. Those videos play automatically when opening the page as expected, but every following page that contains a video requires it to be manually clicked on in order to play, despite the settings "the page with the content is open".

This used to work just fine, I've created many PDFs with embedded videos that autoplayed on multiple pages, little to no issue.. If something changed in that regard, do let me know, but I see no reason this shouldn't work with the steps I've taken.

Adobe Acrobat Version: 2023.008.20470

Videos: mp4 H.264 AAC 
the videos are sized between 2,7MB and 30MB. I've tried only with smaller videos, but this makes absolutely no difference, still the same issue..

I've also tried in an entirely separate 'naked' PDF, same problem. Only the first instance of videos will play when the page is opened, all following videos need to be clicked to play despite the same settings. 

Appreciate any advice or information if something about Rich Media / video embedding has changed or is no longer supported. I can upload a test PDF if required, too.