There are too many variables for someone on a forum to be able to answer. All single coil guitars will produce some amount of noise especially when the volume is up high, but the problem could be instrument cables, patch cables, pedals, the pedals' power supply, the amp itself, the power in the room or the building, and the many hundreds of overlapping electrical fields in the vicinity. I even had a situation once where two pedals interfered with each other and moving them farther apart fixed it.
This is different from a grounding issue, or the well-known issue with the material the Silver Sky pickguard is made of being extremely prone to static. It could be anything. All you can really do is swap things out until you figure out what it is.
Positions 2 and 4 cancel much of the noise, but not all of it.
As JM said in a SS video, the single coil noise is familiar to all guitarists and it's like the sound of someone breathing, you only notice it when there's nothing else to listen to.
If you check out some "guitar isolated" videos on Youtube you'll hear this too. I never noticed how much 60 cycle hum is on some of my favorite recordings until I started watching those.