J,
The valve is the above pic is your Return valve. The other automated valve that is in front of the pump is called the Intake valve. Here is how they should work together.
In the Pool mode, the Intake valve should be set to suck water from the pool and the Return valve should be set to send the water back to the Pool.
In the Spa mode, the Intake valve should be set to suck water from the Spa and the Return valve should be set to send the water back to the Spa.
These valves have to move together in sync.
The little toggle switch is not there for you to routinely move the valve, it is there so that you can initially set the valve in the correct position. After that, you should never need to use the toggle switch again.
Given your day job, the smart thing to do is to replace the actuator on the valve that does not work, or have it replaced.
If you really want to troubleshoot some more, you can go into your automation and swap the cables going to the Intake and Return connectors inside the automation. Then switch between the pool mode and spa mode and see what happens.
If the bad actuator is still bad, and the good actuator is still good, it means the actuator on the valve that does not move is bad.
If the bad actuator works and the good actuator is now bad, then your automation system is the problem.
Thanks,
Jim R.