So, I suspect this is a hardware limitation, but I pretty much always leave my mk3 switched on on the unit, and rely on the USB power from the PC to power it. However, while, when switching on the PC the maschine comes on as you would expect, none of the controls will work unless I power cycle the hardware (either unplugging the USB cable to switching the unit off and on).
Is this a firmware bug with the maschine mk3 hardware itself, in that, somehow the MCU(s) handling input from the control surfaces isnt(arent) initialized without pressing the power button? or a limitation of the mashine hardware (do some MCUs on board require a short period to boot, before the main controller chip can talk to them, and this needs to happen in a specific order?)