echappist

What is the proper etiquette when one is overtaken, but the overtaker does not accelerate away fast enough?

I was overtaken early during my race today. No big deal, i move over to the right (by 2 ft), the passing rider moves forward; all is good. Then for some reason he doesn't accelerate to move away and was in my drafting zone for quite awhile. I actually dropped wattage, hoping that he'd power away, but he was not far ahead of me for about a good mile. It took him 0.3 miles to cover the 2 seconds needed to over take me, but 0.6 miles to move 2 seconds ahead (which is slightly more than 25 meters during the race), where I actually reduced power after he passed me. Even when he was out of the draft zone, he still didn't fully ride away. His power file showed that he ran a positive split, with the 3 miles he needed to make up 30 seconds on me about 30W higher than his power after overtaking (this include the start, the power difference was 20W once he was at cruising speed). I was doing a negative split, so I was actually going less slowly after as the race went on. Before the passing, he was doing 29.6 mph while I did 27.7 mph. In the last four miles of the race (when he was more than 10 second ahead), he was doing 30.2 mph while I did 29.6 mph.

In contrast, when I was passed by someone else at another race, the passing rider sailed away so fast that he wasn't to be seen again. I actually upped my watts after being passed since I needed to pass another rider, but the rider who passed me maintained his 30.6 mph speed throughout and was consistently a good 2 mph faster.

My question is, what should I have done differently here (assuming if there's anything I could have done). Not many bother to look up the Strava Playback data, but one can notice an inflection point or sort when he passes me. And that looks incriminating even if I tried my best not to draft off of people...