@jason.shoes Welcome to the group, Jason.
This has come up before and I’ll try to remember all the advice provided. I guess the first thing to do is to check that, when you run the x gantry to the back (or front) of the y gantries, is the x gantry square to the y gantries? If it is not, you need to move one of the Y gantries backwards or forwards until it is.
If the X gantry is square to the Y gantries when it is at one of the endstops, switch the wires on the Y motors and see if the problem switches with them. Meaning, in your picture, does the 298 move to the left side and the 300 to right right. If it does, check the motor wiring to ensure it is firmly plugged in. Check the dipswitches on the controller to make sure that they are correct. Change each switch, then move it back to ensure that they are all firmly where they should be.
If the problem does not move to the other side when you switch the wires, then you need to check a couple of things on your Y axes:
check the delrin wheels to ensure that one side is not too tight
check the anti-backlash nuts for the same issue
check the coupler between the motor and the lead screw to make sure that there is no slippage
That’s all that I can remember for now. Others may add to this list. Let us know how you make out.