Sometimes on the 100 valve the seat will crack. That's the part the diaphragm pushes against. Take the valve back apart and look very closely at the diaphram and seat. Look for a hairline crack in the seat or an impression in the seat washer of the crack. No way to fix a cracked seat. You'll need to swap out the whole valve. I find the crack is usually at 12 oclock but not always.
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There's a rare possibility the controller itself is sending a weak signal while it's off to the valves causing them to weep.