We have designed our locking mechanism to snap into place every half turn - preventing it from accidentally coming loose over time.
Using one of the wave washers that come with every Orbitkey would help keep the keys in line, making it easier to swivel the keys in an out of the orbit. Usually, when the keys are misaligned (i.e. not fully flat), the screwhead sticks out from it's groove, there is tendency for it to become loose.
Also, the correct orientation for the locking mechanism should be sitting flushed on the fixed metal hub on the band.
If there's a space between the band and the screw/shaft you will need to turn it so that it sits snugly on the groove. See below photo: the top side shows the screw not sitting flushed in the hub.