Share 'Single coil hum'

Hi Guys,  hope everyone is doing great.  I've got what I think is an odd problem. I've just screened a Strat for the usual hum problem. I've done lots of these and I've always been happy with the result. But this one has developed a hum when I touch the pole pieces.  This is a new Strat, I don't think this particular low hum was there before.  Anyone got any thoughts on what's happening here? I'm…