Landyacht, you have to try and outsmart the geniuses that design problems into the circuit.
Wire-in a timer BYPASS. Here I go again...An Intermatic spring wound timer. I like the 12-hour model because when something wears out, gets traded in or catches fire, I can use the 12-hour timer to do anything - I figured out that I can set it for something less than 12-hours, anywhere I like in fact ;
When your solar voltage irregulator says "I smart! I quit now!" Twist the dial on the timer and allow full panel voltage to go in and clean up after the maid.
If you want to do this automatically I have seen several inexpensive 7-day interval timers (12 volt) that will do this automatically.