Back ground video speeding up

I have used an 11 second background video with text and very simple images inserted using a YouTube URL. When saved and viewed in either a mobile or desktop browser, after one or two loops it suddenly speeds up in places. I'm not sure why this is happening. Can anyone help please?

Im having the same issue. Looks good for a few loops, then does a crazy speedup.

I'd recommend using a video editing software and building the loop 10 times there and use this video for better performance and less stream reloads.

PS: unfortunately most mobile browser block video background loops now