It is really sporadic and highly unreliable.

Was lucky to get 1 OV each at 7-11 to wrap up the Chase Freedom quarterly promo.

At a regular store, one OV worked on 1st swipe but the next one failed on 3 swipes. These were done at Kate.

At a neighborhood store, tried the previously failed one at Kate, failed on 3 swipes. Tried at the CS failed on both swipes. Later exchanged it with WDMO at grocery store without any glitch.