www.bettersigns.com makes blanks of all kinds from a lot of different materials and they are in NH
I have..I could do a better job with a chainsaw.
Have you called that vendor yet? Most would take care of the problem.
At the risk of being a spoil sport, have you checked your file? If this is in the same place on numerous parts, it's possible that there is an extra point in the file, magnified by the diameter of the router bit, that's causing that problem. I've had it happen with a very good supplier.