Here's my thought. First thing there has to be a circuit breaker for the converter in the power panel. Use that circuit breaker to turn your converter on/off. Second thought is that at 10:00 AM you are reading the output of the solar controller, not battery voltage. Why does that matter? You don't really know what the batteries are doing and what charge is in them. One way to "test" is simply turn the breaker off for the converter after dark thirty when the solar controller shuts off. Run the vent fan or something a few minutes to get the "top charge" off the batteries. Then check with a voltmeter, DVM, at the batteries and take a specific gravity reading of each cell the next morning after disconnecting the NEG battery lead the night before. That will actually tell you how your batteries are living and breathing.
I do recommend that you install a switchable circuit breaker on each NEG lead of the Zamp controller. That allows you to fudge with the batteries without worrying about the solar panel or climbing on the roof to unplug it. That also allows you to remove the solar output completely from the charging of batteries. Very helpful when boondocked and you turn on the generator in the Morning to bulk charge the batteries. That's because the Zamp has no on/off switch and it turns on at first light. It will put charge voltage on the batteries which will force the converter into float mode as it recognizes the solar controller voltage as the voltage of the batteries and goes right into float or maintenance mode. Generally speaking the Zamp controller is OK but it provides no ON/OFF switch and you must provide a way to isolate it. In my testing it seems the solar controller always over rides the converter during the daytime unless you have the remote pendant for the converter. That little pendant will allow you to force the converter into BULK charge mode. Otherwise with only one or two solar panels the Zamp PWM is OK but WGO kinda did it backwards. The controller should be right near the batteries with a short output circuit run and the panels operating at 19VDC will not be as impacted over a longer 8 ga wire run. In a nutshell during daylight hours you may as well leave the converter breaker OFF because the solar is charging, not the converter. It doesn't matter whether you are on shore or genny. Just plugging into shore during daytime hours or running the genny does not shut off the Zamp. You can verify this operation by using a clamp meter at the battery most NEG ground lead and taking the steps given, what I did.