Apparently his in-ear monitor wasn't working so he wasn't able to hear himself/the music. If you rewatch, you can see that when the first chorus started, he was already checking his ear-piece, and right after that he was checking the receiving unit on his belt (which he also checked again later in the performance, too). It bears noting there was another band earlier in the evening that also had monitoring issues (and some other artists were lip-syncing, as is common with certain types of pop acts for these TV performances, so it wasn't obvious even if they had the same issue).
Yeah, I noticed that. There was a huge improvement, but I also saw him choughing, so I assume he wasn't in perfect shape. I'm really waiting for some live video and the CD to arrive! I like the sound I'm hearing from the previews!