VW Passat 2015 blue smoke during and after DPF Regen

[Shani12]

I have a VW passat 2015 diesel. DPF start regen after every 5 or 6 miles. When regen complete it blasts blue smoke. Engine oil level drops as well.so i have to top it up to correct level appx 1 ltr after 1500 miles. Car runs fine. No limp mode, what would be the reason for oil level drops and blue smoke ? No oil leakage on the floor or engine bay. Piston looks fine as the car has power to run !!