I haven't done any testing on this but the corrosion hypothesis seems plausible. I wouldn't store it under alcohol because there's generally some dissolved wate

I haven't done any testing on this but the corrosion hypothesis seems plausible. I wouldn't store it under alcohol because there's generally some dissolved water/oxygen/salt in there which would cause corrosion. Oil immersion or even a light coat after use would probably work better and alcohol at preventing corrosion.