Irrigation systems should not be installed from the internal plumbing of a house, for many reasons including pressure drop and scrubbing. The Everydrop meter is rated for 350PSI. I find it hard to believe the unit was leaking a higher static pressure (what 100PSI?) but not at 60PSI? More likely it got wet from an external event.
To answer this question, I’d agree either the unit has gotten wet, or its been wired backwards. If it was working and then stopped without being touched, unlikely to be a backwards wiring issue. As for voltage, its an AC voltage not DC, so if you’re reading 38V Peak as DC, that happens to be 25V RMS which is close enough to expected 24VAC nominal.
I’d be inclined to think the wirenuts connecting the flow meter aren’t making a good connection if the screen isn’t coming on and you have voltage at the wires feeding the meter. Also make sure the wires aren’t badly corroded…you can scratch the copper with a knife or screwdriver. Or ideally sandpaper/steelwool.