Ray, I do see a similar thing. I know it's Mach related because I have used a couple different CAM's and produced similar actions by Mach. This is with two totally different PP's. I have searched for dwell actions and can't find any reason for it. It is dang sure a quirk. Minor though as quirks go in Mach. The major points are that it homes correctly and operates the spindle as it should. Not trivial when you consider it works right for rigid tapping. Granted I have only tried RT with Sheetcam and Les modified a special post to do it. I will soon see if Fusion 360 can handle it as well. I play with it (Fusion) every day for a little bit.