IS 220d blue smoke kick

[aureora_v1]

Hi there,
Hoping guys for help and some suggestions what it could be.
Lately my lexus is kicking out blue smoke, BUT THAT DOESN'T HAPPENS OFTEN.

I while i go i went to London and there start my issue, after 1 hour sitting on traffic (with air con on - don`t know if i need to mention that but..) it was suddenly start smoking a lot, till i get it back on road actually moving until now and i have no idea where to begin to find a problem,

Basically he is kicking out blue smoke only if car stays on one place running, (sometime it happens even after 5 min on minor traffic, sometimes it can take 10-15 min).
It doesn`t smoke at all if you are constantly driving.

OIL LEVEL DOESN`T CHANGES, NO LEAKS OR MISSING OIL - SO NO OIL TOPPING AT ALL. NO POWER LOSE OR SOME SIDE EFFECTS

 

PLEASE HELP.

THANKS.