Boeing 757-200 (G-POWH)

Is this exhaust normal?

Is that "exhaust" is air spinning?

Those are wing vapours not exhaust. Also called wing vortices they are most common when the aircraft is generating lift, seems like the 57's create them near the edge of the flaps, I'm not completely sure why. Most A/C it occurs at the wing tips and fairly certain the higher the humidity the more prominent they are. Basically caused by the interaction between the high and low pressure on the top and bottom of the wing.