Simply didn’t take the time to wipe them out. I created these sheets for work, years ago, and use the macros for various functions of my work. These were paired down and cleaned up a bit to submit.
One other way is to use three of the four jaws to clamp a vee block. The fourth jaw will hold the square stock against the vee block. This way you only have to loosen one jaw and gives a positive register for the stock.