I'll try, this is my understanding of how the zamp works, someone please correct me if I'm wrong. Your batteries are fully charged at 13.2 volts, the monitor we have is just showing charging voltage, when it's charging, without a separate monitor going through a shunt you can't get an accurate percentage of battery left while the battery is being charged, wether its solar or shore power. When you get up first thing in the morning your on board converter (shore power) probably had your batteries in float status at 13.2 volts, when the solar wakes up its going to try to bring the charging voltage up to around 14 volts (in full sunlight)until it goes back into float mode and that blue light will go off, I'm not real sure what that bar across the top does.
What I do in lieu of a separate monitor (I agree with Reed Lukens that we should have gotten one, but I digress), if I get up in the middle of the night when there are no loads on the batteries, no lights, tv, etc. I'll check battery status, if we're boondocking, but if you're on shore power it's meaningless because your converter/charger is charging your batteries wether it's in float, bulk or absorb mode, and you can't get an accurate reading when there is active charging going on.
On the other hand, I could be completely wrong, and your converter/charger failed and the solar is trying to top off your batteries.
Good luck, STEVE.