2 weeks ago i switched from the asics hyperspeeds (no issues at all) to the nike streak 3s. both are equally minimal flats (if anything the streak is probably slightly more supportive) so i figured i wouldn’t encounter any problems at all. since then ive sprained my left ankle twice, and am barely able to walk on it. is it the shoe or just a streak of bad luck?
The curvature of the lasts may be different, making it easier for you to roll your ankle with the Nikes (I assume the sprians are due to lateral rolling of the ankle). Match the two up and see if the Nikes have a more curved last.