So it works now... I left everything off for about three hours and somehow it has healed itself. I checked the parallel cable when I went out, but other than that I simply followed my normal startup routine. The machine homed as it should on the first attempt, and I subsequently homed it at least 7 times from various x,y,z locations with no incidents.
Could my issue have been heat related? The machine had been running steadily for about 3.5 hours prior to my observation of the problem:
3/4" 3fl T2-PM-33012 PCT square end TiCN end-mill
Climb cutting with virually no slots
25% step-over at 7 ipm cutting and 2.7 ipm helix engage
Depth-of-cut between 0.1 and 0.05
Fog-buster blowing mostly air
There were very few rapids in my program and at no time did the machine appear strained. My parameters may be a little different than what would be considered normal perhaps? I just got the X4+ a few weeks ago and am still pretty green...
I guess all I can do is see how it goes tomorrow. I have three more of the same operation to run so we will see what happens. Any advice??