We were using Han and Stetman. I had upgraded jet pack and set all reapers to hotkey 2.Then I don’t know when all the reapers in hotkey 2 lost the ability to fly. New built reapers still can fly. Then set them to hotkey 2 and the ability disappeared. Choosing units by mouse , the ability was back,but only some of them could fly.I guess switching Stetzones cause this bug.