Heatsinks for MKR WAN 1310

[kmin]

@soothingmist

Could that have done it? But, that worked very well for a long time and was done about a month ago.

Yes. Possible.
I don't know your board, but I expect that abuse on adc pin doesn't cause rapid failure of the chip.

@soothingmist

The voltage measured at that port is somewhat above the USB standard

That's passing through voltage regulator, so I wouldn't expect problem there.