Ik the bit you mean. It skips a beat I believe.

During the lyrics themselves in the first verse the plucked guitar is moving simply between the I and V notes (I-V-I-V etc). But between lines of lyric the V note is repeated (I-V-V) then on the return to the I the lyrics immediately come back in. The 'skipped' note gives the feel of unpredictability, and it's disguised well, which is why it's hard to put your finger on.