Bike dies when trying to wheelie

I first really noticed the problem about a week ago I was running low on fuel and decided to pump up at the regular gas station around the corner from the OHV area where I like to ride. After pumping up I went to ride and tried to do drills. Put my front wheel on top of a 4ft rock and back down again. Tried a second time on a different rock and the bike's engine died as soon as I applied throttle. After that any subsequent attempt at applying fast blips of throttle would cause the engine to die. If I apply the throttle more slowly at first and then WOT it works fine. So I continued riding and the bike behaved just fine. When I came back to the same spot to try doing a wheelie again, the same thing happened where the first time I applied a strong blip of throttle the front wheel comes up but any subsequent time I apply a quick blip of ~10% throttle the engine dies. I continued to ride around the trails and there were no other issues. I have a PowerCommander installed (PCFC) so when I came back home I tried different mapping and could repro the issue. I could also repro and have the engine die if I blipped the throttle 10-20 times in quick succession (10-20% throttle). When I did that I noticed that the RPMs would not go as high up when I blipped the throttle on the 9th time compared to the first and there was a slight delay in the engine noise compared to when I blipped the throttle (maybe I am misreading it). Any subsequent blip of throttle after starting the bike would result in the engine dying right away. If I wait long enough without the bike running, the issue goes away. If I start the bike up right away after the engine had died and apply a little bit of throttle at first and then any amount of throttle works.

After playing with the mapping (including zeroing out the map) and gears (including neutral), the next step for me was to check the spark plug and air filter. Air filter box was dirty but air filter was ok. The spark plug had some white residue so maybe it's running lean? The spark plug was also out of spec (0.8-0.9mm). I adjusted the plug to be in spec but that didn't help the problem, although I did notice the bike running stronger when I changed to a better fuel map and adjusted the plug. The easy part for me is that I have two WR250Rs with almost the same configuration so I can always compare.

I would appreciate some ideas on what this can be. I have had people tell me it could be a bad fuel pump, vapour lock, air in the fuel line, bad fuel, needs a better rider, etc...

Recent Maintenance:
1. Changed AirFilter
2. Changed Coolant and swapped Radiator.
3. Plugged one of the throttle body vent hoses that was plugged on the other WRRs.
4. Swapped Subframe (old one had a crack in it)

Other relevant maintenance:
Changed Spark plug less than a year ago.

Spark plug right after I took it out:

So fun update in case anyone ever has this problem. The issue was a damaged kickstand sensor plug. It was not falling out completely, but it was momentarily disengaging sometimes, especially when the bike was being used more playfully and compressing for a wheelie. I ended up just shorting that wire and removing the actual sensor.