Twisted Corner: FrameShop Definition

A Twisted Corner is when the blade turns before retracting from the matboard, which tears the matboard and twists the corner. This is especially visible from the back of the mat.

Check to make sure the Rotation hasn't been set to a high number. 

Optionally, see the Clean the Foot Block procedure for information on cleaning the foot block. 

Twisted corners can also be a symptom of oil/water in the Air Valve, or an issue with the Head. Check the Air Regulator for excess water.