I feel like it could be from the car NEVER going wide open throttle with that much E85 for the first time. Your motor has only seen pump gas so under WOT something like that could be possible. But honestly I think you just had a misfire from what you are describing. Find out when the last time the plugs were changed and also find out if your car has had the HPFP/injector recall. On a tuned car the general rule for plugs if I'm not mistaken is 10k-15k miles. I do mine every 10, well last time was 12k miles.
From what I understand, BMW scans your injector to see if it is a "failed unit" and then replace it but usually only THAT injector. Thank God my service advisor and I are buddies growing up and I had ALL mine replaced
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[SIZE="2"]Crimson Red E92 335i M-sport 6-speed with MHD custom stage 2+ flash only , 40% E85/93 mix,+ HRE P40S wheels, KW Clubsport, M3 sways,+BMW performance CF Mirrors, BMW Performance CF deck lid spoiler,+ CF interior trim, p3 vent boost gauge,+ LUX angel eyes (11.73@124mph on street tires)