Since you did not affirm or deny the alleged procedure, nobody here will be able to answer the "sound right" part. Generally, valves accumulate moisture from the air compressor. The valve is a baffle with tortured passages. Because the valve is made of a metal with high conductivity it tends to shed heat rapidly. Air which encounters an obstacle which then forces it to change speed and direction tends to lose humidity in the form of condensate. Loss of energy (heat) may accellerate this process. There is a popular conception that "adiabatic" heating occurs when air encounters obstacles. However, if this were true in your particular case, the water would have been found in the tank. No, the likely cause is humidity originating in the compressor. Small amounts are deposited in eddy areas or entrapments. Water will not form in the working parts of a cold valve which has been removed from the tank because ingress of humid air is blocked by the valve seat. However, it is possible that a tiny amount would form in the orifice. This would be blown through into the tank and the valve would tend to dry out if the compressor air is very dry as it should be. I should point out that corrosion is sometimes found in a valve but it is unusual for it to be so severe to cause a problem. Cleaning and lubing lightly with Christolube should take about 10 minutes. Sometimes a copper washer or O ring needs to be replaced. Sometimes, replacement of the relief valve is undertaken.
