If it is stopping randomly before even reaching the home switch, and increasing the debounce interval helped, that pretty much confirmed that the problem is in shielding / crosstalk, probably with the stepper leads for that axis.
Debounce is intended to compensate for contact bounce in the switch when it is triggered, not for crosstalk. Increasing the debounce interval further will reduce the symptoms of the problem, but will do nothing to cure the underlying problem.
What you should do is inspect the routing of the wires for the home and limit switches on the problem axis to insure they are kept as separate from the stepper wires as practical. If it is not practical to physically separate the wiring then the wiring for the switches should be changed to shielded wire with the shield grounded at only one end, generally the control end.
Also note that the crosstalk can be occurring anywhere along the wire, not necessarily just where they meet on the axis. If the wires are close on the control end that could also be the source of the crosstalk.
Pete C.