I'm using a Pokeys57CNC v2.0 with Firmware v4.5.0. I have the probe connected to Pin19 and everything set in Mach4. The diagnostic window shows a connection the moment the probe touches the work piece and the log shows Signal id 161 (Probe) changed from LOW to HIGH.

The problem I'm having is if I run G31 through MDI the axis doesn't stop until it reaches the set number regardless of the probe signal. The touch screen and the probe module all produce the same result. I'm certain I'm missing something likely obvious but I'm not even sure where to go from here.

I did have similar issue the other day, when I was probing tool it went true pass the signal from the probe (good I have E-Stop on the probe as well)
That did happen when i was using MDI
The problem was the G code

G91 G31 G1 Z-30 F150 -when I did in this order It did crash
G91 G1 G31 Z-30 F150 - works without issue

Hope that will help

did you make M function and try run from Mdi or run directly G31 from Mdi?
i work with pokeys cnc 3 years many many machines alot with G31 not have any problem