I’m with @DLane, sounds like an intermittent issue caused by a faulty valve. The fact that valve continues to operate without Rachio power and in a different (new) zone connection indicates that issue lies with the valve.
Valves seldom fail reliably (completely), most of the time the works get clogged up and valve starts misbehaving (such as getting stuck in the open position). Correlation =/= causation and the fact the valve has worked when tested with the old controller does not mean that the old controller has caused it to work.
I would try to unscrew the solenoid and run the zone (in case you have a master valve), there will be plenty of water coming out of the solenoid opening, but that water will hopefully flush out any debris causing the issue.
Check the rubber gasket on the bottom of the solenoid and replace the the gasket / solenoid if needed.
Should the issue persist after flushing the solenoid opening, you may need to disassemble the valve to clean it completely. There are plenty of videos on youtube such as this one (link) which show how to do it. Most of the valves are similar in this reguard, but you can try to find a video specific for your valve model.
Cheers,
Gene