First, I do not know, it has been caused by an Inverter or a Panel,
but, I am suspecting that the problem is happening by The Inverter.
Everybody know the shadow can reduce the power gain from Solar Panel,
What will happen there is very small shadow 1-2 cells in a 60 cells panel ?
Yes, it can reduce the production to 30~60%,
Look at the detail production yield at my house,
Sunlight is coming from Right-Top side and, Dommer at Right Hand Side is making a shadow on Panel #6,
#1, at 09:19AM, half of two cells (right-top side) are shade, power production is just 10% via the other panel.
#2, at 10:23AM, very thin shade on a cels (aroudn 10~20% on right-top side), production is 80% via the other panel.
#3, at 10:29AM, no shades, same power gain via the other panel.
In the solar panel test with MPPT charger, the minimum power is aroudn 60% in #1, 90% in #2
It makes me suspect There is a critical problem in Enphase IQ inverter.
Note. Enphase IQ 7+, LG350N1C-V5