Y losing position at start of program

I just received my woodworker and trying to get my spoilboard set up. I home machine and then probe x,y,and z near the home position. I’m trying to bore my dog holes. First hole is at back of machine around y 770 mm.
I start program and it heads off to the first position. It gets about 100mm in y, then stops with a clunk and a loud whining noise and goes down to bore the first hole. It’s only at y 100mm or so but readout shows it a y770mm.
Anyone know why this is happening?

Could be a number of things, since you are just getting set up I’d make sure the Y rails on the left and right are parallel and you can move the X rail back and forth by hand without it binding (you will need to shut down the controller first). If the rails are parallel and all you might want to try removing the X rail and jogging the y rail back and forth to see if one side is sticking. If all else fails email support.

I thought that was a possibility but I move around with the joy stick and nothing seems sticky or jerky. I powered down the machine and powered back up and reprobed my corner and everything was fine. I’ve also had a couple times when I would home the machine and it goes up in z, moves over in x and then just stops. If I then hit the Y home button it homes as usual.
Just some strange things seem to happen. And if I power down and power back up, it’s fine.

Had somewhat the same issue. Clunking noise occurred in the middle of a carve and wrecked a few pieces. Turns out that the wiring to the Y motor 1 was not making a proper connection. When that happens, the one motor turns and the other quits resulting in the y axis stall. The controller interprets this as the y axis moving even though it stalled, resulting in the toolpath being off. It took a long time to find the issue on mine as it would happen intermittently, but i could never get it to do it with my joystick controller. Finally figured what the issue was when I did a pocketing air tool path at a 45 degree angle. Unplugged the X stepper while running the file and found the issue was the Y.