Still glitching out

ok this is super frustrating…
detailed 3d carve comes out flawless. exact same material (walnut), exact same settings, the next carve its just all over the place on the roughing pass.
Started out fine, got through two passes with out a problem and then the X axis shifted a half inch to the left. plenty of empty space so I let it ride to try and see what it will do. notice a slight stutter like movement when milling along the x axis moving from right to left. not like major hiccups but very noticeable and you can feel it if you have your hand on the enclosure.
!0 minutes later i walk away and come back to all hell breaking loose and now my Y axis has shifted to the point where its carved beyond the work material at the top and the bottom and appears to have restarted the job WAY north of center.
Cut settings for roughing were:
32in/ min feed
12 in/min plunge
step over at 40%
and depth per pass 0.03

when using easel is the gcode sent from the internet or is it downloaded to the computer and then sent to the carvey locally? could it be possible that a weak wifi signal might be throwing the wrench in the works?

Could the little hiccups be causing missed steps , and is there away to dial the current back for the steppers as the internet suggest for other cnc machines?
Bad usb cable?
Sawdust and such gumming up the rails/bearings of the X axis?
The carvey sucks and is pretty much the same thing as my 3018 only with a marginally bigger build volume a fancy looking box and a hard wired dependence on easel as its gcode sender?
all of the above?
help! lol