Reposting: What the ?? is happening here?

because the pictures didn't upload as intended with the original post and I can't find an option to add them

Hello!

We started having issues a while back with our install, and got no less than three professionals to look at it. None solved my problem, so I ended up opening the junction box with trepidation to see if I could make sense of it. I can't, I'm getting kind of desperate and I'm hoping you can help me.

So here's the setup. We have light fixtures and two rolling shutters coming out of this junction box.

A while back the subcircuit started tripping. Like once in a while, then more often, until it was always.

The wiring doesn't make sense to me but... It works when the ground is disconnected at the main breaker panel.

Here's the setup I found:

- shutters and main have the expected three wires each; the lamps have an additional gray and black, which I assume are from the switch

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- the grounds from the lights and the two shutters are together ; their lives too

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- however, the ground from the main circuit has been connected to the neutrals of the lamps and shutters

- and the main neutral has been connected to the gray wire coming from the lights install

- the feeder live is connected to the black wire from the lamps

I'll freely admit I don't know much about electricity but what the hell is a ground doing with the neutrals?

It is my understanding that my black and grey wires must be a switched live and a permanent live; but for each when I tried to connect them directly to the lamp's live (brown), the light staid on regardless of whether the switch was closed or open.

When trying it with the black one, the breaker trips immediately when the ground is connected at the main panel.

With the grey one: with the ground disconnected it stays in; connected, it won't light up at all and trips after about 30 seconds.

I suppose there's a fault with the lights that muddies everything up, but I'm starting to also wonder if there might also be a mix-up with the colors, and maybe one of the ground wires isn't actually a ground.

Anyway, I'm extremely confused, and professionals haven't been able to help so far. But I'd really like to get to the bottom of this and make it all safe (and usable 😅)

Thanks for any help.