If the ball hits a part of the body (knee or head, whatever) and it clearly wasn't going to hit the arm/hand from the original shot or cross but then does because of the ricochet, that to my mind is accidental and no pen.
With the incident on Weds night, yes it did slightly touch Can's head before hitting his arm. However the original cross would still have hit the arm if it hadn't touched his head. The arm was in an unnatural position. That is not accidental and is a penalty.
Can tried to handball it and his head got in the way.