OK, I don’t know WHY it’s happened, but for some reason it’s over-calculating your average power.
Weirdly, when I select just the period of the race where you were “working”, the average power comes down from 264 to 237, which makes much more sense:
And if you just select a little bit of the dead time from the start of the workout, click “cut”, and allow it to recalculate, you should see values that makes a lot more sense.
(God only knows why this is happening - a similar thing was going on with me recently which we never really got to the bottom of, except in my case the average power was under-reading. In your case, it’s worth noting that the maximum power on your workouts is listed as 1525, but I can’t for the life of me find any power spikes that high anywhere in there. So that might provide some clue.)