well, if it wasnt wired by a bunch of monkeys (so chances are high), the only draw with the battery disconnect disconnected, would be to the breakaway and 7pin 12v+. by chance was it hooked up to a vehicle when you tried this?
On mine they at least seem to have everything behind the disconnect, but its possible they have a radio memory wire or something wired direct (co/propane/smoke detectors would have been my other guesses)
'14 XLR 395AMP
'16 Ram 3500 DRW, 6.7 cummins w/aisin trans and 4.10 gears