Hard Limit error (Ox router, GRBL V0.9, xPro V2 controller)

Hi all,
I have recently assembled a grbl controlled, Ox router CNC, using an xPro V2 controller (from Spark Concepts) and ChiliPeppr as a gcode sender. All seemed to be working well and I made a successful first cut yesterday. However, after noticing high chatter on the x and y (belt driven) axis, I decided to bridge the decay settings on the board. I immediately began receiving hard limit errors and cannot understand why!

The board gives me a hard limit error immediately when I try to jog any of the axis or run a tool path. With the hard enabled, the homing cycle runs fine but from what I understand the homing cycle runs independently of the hard limits. When the hard limits are disabled everything works fine but I would like to use the hard limits.

Does anyone have any idea what has gone wrong?

Thank you in advance.