Your rudder could be trimmed to favor one side.
You might not notice it in normal flight. If you are
accustomed to flying with both thumbs, you will
find yourself correcting more on one side in low
speed turns.

Spiral slipstream could also be a factor if there
is not much fin/rudder area below the elevator
(such as elev/stab mounted on the bottom of
the fuselage). Right thrust if there is any, will
tend to negate the spiral slipstream.

Uneven lift (up on one side more than the down
on the other side) is the most likely cause.
Flat bottom wings will need more up aileron
on one side to equal the down aileron plus
wing camber on the other side. (Another
reason to use differential besides adverse yaw.)

Mostly this will make it corkscrew both directions,
but if one wing is twisted or the aileron linkage
is off center such as from trimming to compensate
for the off center rudder, the corkscrew will
be more pronounced on one side.

Finally, exhaust blowing over the wing on one
side can increase the lift of that wing more than
the other side. It is not much, but will add to any
other causes.