Why doesn't the poster for the video work on ios?

Question

iOS

I registered the video tag, I registered a poster for it, and everything works on the PC and Android, the poster is shown. But on ios in safari and chrome, the poster simply does not work if you remove the poster from the html so that the first frame goes like a poster. Then again on PC and android everything works, on ios video without a poster.

It’s just that the cover for the video on ios doesn’t want to work, even if you prescribe a photo separately, even put the first frame, it doesn’t work