Dropping Z axis on E Stop

Hi everyone

If I trigger either the E Stop or any limit switch, everything stops moving as it should but the Z Axis then sinks quite quickly under gravity allowing the still spinning bit to drive through the work piece.

I would expect motion to stop and each axis to hold its position.

I am using Mach3 to drive a chinese all in one board.

Can this be configured differently either in the software, hardware or wiring?

Would appreciate any input. Thanks.

Dave