Detailed description of the problem
When you are clicking on a Video it opens it in the "bigger" (Fullscreen View) but it does not start playing.
There seems to be some invisible buttons (sometimes as gray areas on the top right and left of the Video) and if you are trying to tab on it it sometimes starts playing.
All in all starting a video on iOS isn't really possible.
Steps to reproduce the issue
Output of the diagnostics (Settings => Diagnostics)
Browser and system