Unless is been mentioned, I think they changed the YouTube stream last night. During the pre-show and first half the DOG
clearly said 4K UHD and during the second half it was from the BT Sport 2 HD stream.
There were all sorts of compression issues with the YouTube stream last night when it was being sourced from the UHD feed. Not, I hasten to add, because BT were filming in 25fps and streaming at 30fps and didn't know what they were doing, as one prominent YouTuber was quick to tell everyone was the cause.