it sounds like you have two problems. one is the supply is not completely shut off due to a leaking gate valve or a ball valve slightly open. your main trouble with the sprinkler head is an electric valve on that station that is either partially open manually or the valve may need to be rebuilt or replaced.

Thank you MrHIrrigation

Wouldn't either of the two issues you mention cause other heads to leak as well. I only have one leaking, at least that show signs of leaking - water puddling and pooling around the head. This is not evident on any other head on the system.

usually a low pressure leak like you have will drain at the lowest head on the station. when you turn the supply back on the electric valve will most likely get worse till it fails completely and the station will not shut-off.