Frankly, that's the whole point of the Nh stuff, so you don't have to worry about "getting the fresh out" because the horse won't be uppity, he'll be in the right mind set because of the nh stuff.
But to each their own.
That said,...the problem I see is that you're not putting the release of pressure at the right place and I suspect you might be chasing after the hip which causes the horse to stop and turn to face you.
1) point to your left and cluck/kiss and put pressure on the horse's left shoulder to go to your left. Soon as it turns to your left and the horse is ready to be driven forward, simply look at the hip (don't go after the hip) and put pressure on the hip to go forward.
2) the horse goes forward around you in a circle, and you put the whip to point at the ground, don't hold it up. Every single time the horse stops and turns to face you, look at the same shoulder as before and tell it to move away and set the horse up so then you can drive the hip forward again....repeat repeat repeat. If you stop when the horse stops and turns and faces you, you're giving the horse the wrong message, you're giving him a release of pressure at the wrong time.
You've got to be consistent if you want the horse to understand how you lunge and that means, every time he turns and faces, you tell the SHOULDER to move away, don't go after the hip. So, you should be able to stay relatively in one spot in the arena and send the horse around you....without "chasing" his hip to go forward. If you "chase" the hip, you will cause the horse to stop and turn into you.
If he backs up, follow along (don't play tug of war) and continue to pressure the SHOULDER to move away to then get the horse facing to your left (or your right, whichever direction you're choosing him to go)....soon as he does, stop the pressure for a moment, then put pressure on his hip to drive it forward.
It's got nothing to do with his being trained Parelli or not. Parelli has a step that sends the horse over obstacles without the person doing much movement which is like regular lunging. The real problem is where you are putting the release of pressure.....
Put it where you want it and the horse will understand.
Don't chase the hip.
Start with the shoulder.
Move the shoulder. Then drive the hip. If you're consistent, your horse will understand that the pressure goes away if he doesn't keep turning in toward you or if he doesn't back up. If you wiggle the whip at him and he backs up, then keep wiggling the whip and get to tap the SHOULDER if needed to let the horse know you are not telling him to back up. there's pressure if he backs up = he'll soon understand that backing isn't where there's a release of pressure.
The more consistent you can be, the easier it will be for the horse to comply with how you do things.