Blue Smoke

Finally got the car running like a swiss watch and now another problem has occured. Basically if you rev the car on boost and then shut off there is a delay followed by quite a bit of blue smoke. It just started happening out of the "blue" 3 days ago but hasnt gotten any worse since. If you drive the car off boost it doesnt smoke at all and the dipstick level hasnt dropped. I'm thinking its either piston rings, turbo or stem seals??? However the car is running better than ever and there is no loss in power so im assuming its not the rings and find it hard to believe the stem seals would go just like that. Lastly I changed the turbo when i changed the engine and there wasnt an ounce of play in the shaft and covered less than 2000 miles since.

I would do a comp test and maybe consider tubby seals and maybe check ic pipes for oil