I suppose I never think about unclipping with a curb to my right. More often than not there is a ditch to my right (or, of course, flat pavement).
So, the right foot remains clipped in for the power take off. Left foot comes out.
While flopping into a ditch might be bad, flopping into a traffic lane is worse.
BE VERY CAREFUL.
If this was to continue to be a problem, then I'd encourage going back to flats, or something else. Pinned pedals are relatively new... at least for me.
Toe clips, and heel down, and the foot usually goes straight out and down.