It looks as if the edges of the wood have a slight round over on the edge. If that is the case it may not be rolling properly on the sensor, in one of the pictures above it looks like the roller left an impression in the wood really heavily and then almost disappears towards the upper part of the picture, maybe the edge is not straight enough with that round over. did you turn the wood over and try it, or are the marks that I am seeing from something else?
Most folks are afraid of heights, me I fear width.