I understand what Andythecornbread is saying . . but in this case I think he has learned this as a trick, an evasion, not as any kind of misunderstanding with you 'sending him away'. Of course, I'd have to actually witness the whole process to truly know what is happening.
I had a hrose somewhat like this. He was cunning. I know we are not supposed to use such descriptions of horses, but he was. He knew exactly the moment when I was not paying enough attention to stop his plans before execution. He'd whip his head around , away from me, line up his whole body behind that head, and nothing short of a tractor could stop him from ripping the line out of my hand and thundering off.
He did this usually to avoid loading into the trailer. So, it was not some kind of 'play' for him, but a technique he had learned worked to avoid something he found worrisome.
If I kept him in a close circle when lunging , or trailer loading prep, and I made sure that his head was ALWAYS tipped toward me and was stepping both forwad and away from me ( crabwalking), then I had that split second to shut down his thought to swing and bolt. But, darn! I had to be really sharp on it. I had to keep his thought and his head tipped in at ALL TIMES!
What I eventually did was just use a chain over his nose, with a short brief shank when he was thinking of this, to remind him of what I COULD do. I'm sorry, I used force and pain. But, he was an older horse whose habits were learned, and I only needed him to participate for very short times.
So, you can work with him on this keeping his head tipped in ALL the time. you can add a chain, or put the lead line up over his nose. I think that working more on his yielding of the shoulder will be very helpful, as this is rreally waht you are doing when you ask them to circle but also to step out ward (that 'crabwalk thing")
This is often called 'drifting the shoulder' in some western parlance.