Strange vp2 behaviour

[raymew]

Just installed a fox ecs-h1-3.7 hybrid system with 2 strings of 6, 545w panels, it’s been running since January but only just thought to interrogate the individual string performance, and realised that string PV2 has never contributed anything from the start. I checked the power on each string and both are generating all the way up to the PV inputs on the inverter.
I moved the PV2 string over to the PV1 input, and it started to generate. I connected the PV1 string to the PV2 input, and it did not generate.
I checked that the settings for the strings were set to independent, OK
On the inverter during operation the values on PV2 are 8.6v 0.0A and 0w (which would indicate a string wiring fault)

I contacted FOX TECHNICAL talked it through with them, they logged on to the inverter and interrogated it to confirm what I was reporting, and at their request forwarded all relevant readings and full videos of the testing.

FOX agreed that it must be an internal fault on the inverter, and immediately dispatched a replacement inverter, which arrived in 2 days.

I exchanged the inverters, AND HERE IS THE STRANGE THING ! ITS STILL THE SAME.
Can anyone tell me what I have missed please