I have not seen this exact glitch mentioned at all, but whenever I press a video, it plays the audio, but the thumbnail stays. Audio, but no video, only a static image. I have to move to another app and then back to YouTube for the thumbnail to go away and the actual video to play. It also pauses playlists at random videos. One day it will pause a playlist at the 3rd video and the next day it'll be the 7th video. The thumbnail thing is also only on mobile, it plays continuously on PC.