Clicking problem on a 1997 Parker Fly Deluxe

Here's a little puzzle for all you bored quarantined guitar detectives looking for a challenge!

Some of you know that I have a Parker guitar.
It's an import PM20 Hornet, not one of the top end American made Fly models, that would require a second mortgage to purchase!

I know bugger all about the Fly designs, they are really unique. But I casually follow the goings on over at the Fly Clone Project Forum and interesting problems arise from time to time.

A Forum member from Glasgow just posted about a "clicking" problem he's having with his Deluxe model:

Alan at The Fly Clone Project wrote:
Hi Guys

I had some electrical issues with my 1997 Fly Deluxe earlier this year. One of them was due to a faulty piezo saddle which I replaced and that fixed the problem. However, I still have the other issue which affects only the magnetic pickups. Now that everything else is working fine this mag pickup problem is driving me crazy.

I have made a video to demonstrate it.

[see below]

Has anyone else ever experienced this clicking noise and if so how did you fix it?

If not, can anyone with knowledge of the schematic figure out what would be causing it?

I love the guitar but at the moment it is basically unusable due to the noise.

Thanks

Alan

My first thought of course was that it's a grounding issue, but it doesn't seem to be straight forward where or why.
Faulty pickup maybe? Gone microphonic?
This guitar also has a piezo circuit. Some sort of weird circuit polling interplay there?

What do ya think is going on?

Nope.... no idea! Dodgy pot, maybe?

Weird one ain't it?