Pulled right from the M2 manual:
"AutoLatch is active during the fist 60s of PC operation (and only during the
first 60 seconds). For example, If Ignition is turned ON and then OFF right
away, M2-ATX will latch Ignition in ON position for the next 60 seconds"
So when you go to ACC, that triggers the PC start, if you leave it in ACC for more than 60 secs, you loose the latch feature, then when you go to "run" that on-off-on will trigger another PC start. Add a "always on switch" and flip it on before moving the key then slip it back off again.
It's no different than if you had a head unit installed (depending on the head unit).