@JacobE1988 (Related to BlackBox) You don't maybe have a clue on which setting is the one causing all this grief
I've been playing with settings more and I did find one configuration that allows me to stop the spindle, but I'm not sure I feel safe using the settings. If I take PD011 and PD073 and set the minimum frequencies to 0 and have the min spindle speed set in grbl to 0 then the spindle stops on M5. But this seems dangerous to run with an air-cooled spindle if a too low speed gets sent on accident it wouldn't take much to fry the spindle. But I'm hoping this maybe helps point in the right direction.