Apple in iOS 14 added Picture in Picture to the iPhone, a feature designed to let you watch a video in a small screen on your device while you continue to do other things on the phone.
The YouTube app doesn't support Picture in Picture, but up until yesterday there was a functional workaround that allowed videos from YouTube.com to be watched in Safari in Picture in Picture mode.
As of today, that workaround is gone, and it's not clear if it's a bug or a deliberate removal. Attempting to use Picture in Picture on a video on the mobile YouTube website simply doesn't work. Tapping the Picture in Picture button when in full screen mode pops the video out for a second, but it immediately pops back into the website, so it can't be used as a Picture in Picture window.
Picture in Picture in iOS 14 stopped working on iPhone for videos on YouTube’s website. YouTube videos embedded elsewhere still work fine. pic.twitter.com/8vTFy4u3Ut — Eric Slivka (@eslivka) September 18, 2020
Picture in Picture works with YouTube.com on the iPad, and YouTube videos embedded on third-party sites such as MacRumors.com appear to be able to play in Picture in Picture mode, but Picture in Picture is not functioning on the YouTube website.
We tested Picture in Picture with YouTube just yesterday for a Picture in Picture tutorial video and as you can see below, it was working fine. Since then there have been no updates to iOS or Safari, so it's not clear what's going on.
For now, Picture in Picture is no longer working with the mobile YouTube website, but there is another workaround. If you request desktop site on YouTube.com in Safari, you can get Picture in Picture to work as intended.
Update: Picture in Picture appears to work on the mobile YouTube website in Safari for those who are YouTube Premium subscribers, which suggests that the restriction is intentional and not a bug.