Oops, he said he guesses what it is. Here's his response. Never happens tuned so something's getting fixed in the tune.

All those stock values (275-280) are in line with past results found on dynojets. The runs over 300 must be with mods and or tune, but I didn't read carefully.

Little blips in the curve could be anything from wheel slip to signal-pick up noise to a tiny ping -- nothing in there suggests any major issues tho'.