I don't know if this is useful or not, but in the last control system I had it would make crazy spirals and loops whenever I tried to cut a interpolated hole like what I see you are doing. I found an option in the old control setup (not Mach 3) to select Fanuc or Bridgeport style arcs when processing G-Codes. I was using MasterCAM's default post-processor, so in the machine control I selected Fanuc arcs. Is this related to the Q parameter?