It was the third down incompletion (2nd niner drive) where Weddle, who was not physically involved in the pass breakup, walked over and extended a hand to Aiyuk to help him to his feet and he abruptly stood up and purposefully head butted Weddle under his chin with his helmet. You can see Weddle was stunned for a second.

That's when I felt the niners had been given their marching orders.