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Will it be a temporary aberration? I can give one guess but I may be all wet. My background is physical sciences not biochem. If you were well below your calorie goals and also exercising could the energy needed for your exercise have been supplied by glycogenesis of protein? In effect you made your own glucose?

I experience horrible glucose dumps over night... my guess (self-educated, I read everything I can get my hands on, and I absorb this stuff like a sponge) would be that because you exercised LATE at night, and I'm assuming that means after your last meal at 7pm, that while you were sleeping, your body decided it needed glucose - and your liver dumped some in to your bloodstream... read up on Dawn Phenomenon if you haven't or are unfamiliar with this response. My BG numbers used to go up well over 50 points overnight, regardless of what I ate before bed, or if I didn't eat before bed, or when I exercised, etc.... even on 2500mg of Metformin, they'd still go UP over night... just one more friendly reminder that this disease is very unpredictable and different for each one of us... I'm curious to know - how have your morning numbers been since this event? are they back to where you need them to be?