Apart from the two cute Spielberg films, i dont tend to believe in Gremlins. I believe there has to be a cause, be it operating system, electrical, mechanical or whatever-ical.
The only total loss of control instances that I’ve heard of with any all-in-one which then wouldnt replicate the fault elsewhere, or seemed “back to normal” elsewhere, was just down to local electrical issues at the venue/playout location.
One PA system was actually sending (un)reasonably high voltage back up through the master out leads INTO the master outs, causing mayhem.
In another instance, the audio was on a diesel generator being shared with the kitchen equipment (brownouts causing issues all night).
Another was bad earthing/grounding beyond what the little plug-in 3 pin plug-testers would identify - and of course, as soon as the gear is tried elsewhere, on good electrics, it performs fine.
Sometimes these things can take MONTHS to show up and get resolved as you cant start whipping out the electrical tester kit and probing the wall sockets in/around the DJ booth while you’re in the middle of a set. And typically, if the club is tested the next day, the parameters have changed - eg: The club kitchen isnt pulling power in the daytime, the venues hungry air-conditioning isnt running in the day, the extractor fans arn’t pulling a million cubic feet of air out of the venue every minute except during the hours of darkness etc. Sometimes that certain dimmer pack or lighting rack doesnt leak voltage until it’s been running for 4 hours solid etc etc.
The US guys suffer from “dirty mains” more often than some other locations, and typically there are a range of Mains power conditioners, uninterruptible power supplies.which can be obtained and used between a venues power system and the visiting PA user. These are rare in the UK, but not uncommon, and in fact quite regularly used by DJs who perform in marquees and outdoor events. Very often a “simply” uninterruptible power supply for the mixer/all-in-one controller (not on speakers or amps) would help to filter out “dirt” in the mains supply and can often store just enough power to smooth off the highs and lows of brownouts etc.
Ok, if the mixer/all-in-one gives the same odd behaviour in multiple venues, miles apart, then I’d suggest booking the unit into an authorised service centre.