ADS1115 4-channel ADC has 0.925 VDC between GRD and AIN0 whether ever the Pi 3 has power

I have an older Pi 3B running raspbian. I have a weird problem that apparently started when I was gone but the Pi was runnings so I started poking around trying to determine why my Python code which has run for weeks suddenly doesn’t see voltage on the Seeed ADS1115 HAT. As long as the Pi has voltage from the USB adapter there is 0.925 VDC (read by a Klein professional VOM) between GRD and AIN0 with no input voltage.

Thoughts? Did it go bad?

I have a brand new second ADS1115 4-channel HAT and a brand new Raspberry Pi 4. It has about .9 VDC and 1.5 VAC (I didn’t measure this before) with the Pi running and no inputs to the board. What’s going on???