Troubleshooting strange RV solar charge system behavior

After 2 years of running well, my RV solar charge system has stopped working, and has a peculiar behavior: it shows voltage in the early morning and late evening, but voltage goes to zero during direct sunlight. I have tested all 3 of my panels (Allpower 100W flexible, 18V) and they are at 0V in direct sun. I had them connected in series to a Victron SmartSolar MPPT 75/15 charge controller, connected to 2 12V batteries (I planned to change the configuration to parallel and get better batteries this month, but then it all went on the blink). The unit was charging until 2 weeks ago (see graphics below), power kind of dropped down for a week then went to the 0V in direct sun , 11 to 14V in the morning and evening. One thing that’s odd is the power dropped off to zero July 23 and 24, and my weather station recorded 42 lightning strikes July 23, then on July 25 the system started charging again, then dropped off to the current pattern around August 1 or 2. Also, we had 256 strikes nearby on July 18, but it didn’t seem to have any effect. So, I was thinking someone with some knowledge might have a clue why this system is behaving this way… the early morning and late evening voltages are confusing, it even charges the batteries a little sometimes before it shoots down to 0V when hit by direct sun in the morning.
Regards

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