Hmmm, I’m having the issue with both my Telecaster and my Takamine acoustic. Tried all combinations of different cables, speakers, amp, headphones, and a different building entirely (including ONLY a guitar and headphones) and the issue persists.
The hum has all the characteristics of a ground loop: 60Hz, and stops when I touch the metal part of a cable (or when I plug in the Pod Go via USB to my grounded computer).
I bought a $20 ground loop eliminator from amazon, and that successfully stopped the hum. Which should be good enough to get me through a gig-type-of-thing that I’m playing on Saturday.
I opened a support ticket with Line 6 as well, will report back with what I find out!