best guess, you left the inverter turned on
many battery disconnect switches, do NOT disconnect the inverter
it set there running until the batteries got to low, then in it went into alert mode
hence the flashing lights
i suggest you thoroughly read the manuals for all your appliances etc and the operation on things like the inverter
ask questions about what you don't understand
even IF connected to shore power, periodically check the house and ENGINE batteries
many RV's do NOT charge the engine batteries while plugged in, and chassis electronics can drain the start batteries over a period of time as short as two weeks
BTW if you have shorepower plug in, you don't need to disconnect the batteries, and should leave them connected
only use the disconnect for storing with no shore power and NO solar
power