Yes you have got it correct.and you actually mentioned more than one reason.
A wing stalls because the angle of attack of the airflow to the wing exceeds the value where the airflow can stay smoothly attached to the aerofoil and becomes turbulent with a subsequent loss of lift. as you say, one wing may be rigged slightly differently, the aircraft may be yawing, or turning, there could be slipstream effects etc.
( I also note from one of your other posts you say you are a flight instructor, so you should be well aware of the reasons why!)