hhhmmmm...... I did connect the 5v output to A1 input. Read the voltage and broadcast it. MKR WAN 1310 is a 3.3v device. Could that have done it? But, that worked very well for a long time and was done about a month ago.
Another point on your side: Also about a month ago I had connected the MKR to the USB port on a headless Rpi4B. The voltage measured at that port is somewhat above the USB standard. But, again, the device worked well for a long time afterwards and only now has failed.