as far as i know, loons will only disobey these kinds of commands for a reason, in other words, something startles them, there's an enemy around which they've spotted, they belong to a group commander who is behaving in an "aware" manner... but if the loons are on their own, with no enemies around, and with no reason to get jumpy, setbehaviour "safe" will always put the gun on the back. if it doesn't stay on the back, there's something making the loon react.
my only suggestion is that your putting them on "aware" first is somehow making them edgy. do the loons belong to a group in which other loons are still on aware?
it does sound like a very strange problem.... :-\