[ohohyodafarted]

HV is a funny thing. I had a 15gp22 that was ticking around the ultor ring around the front of the tube. Even though the area is shielded by a thick plastic insulator, I was getting HV static leakage. I cleaned the tube and the inside of the plastic HV shield and the problem disappeared. There was evidently a film of barely detectable cigarette smoke on the tubes surface.

I suspect that you may have possibly forced some of the residue from your cleaning into the areas around the tube socket. If it can't be disolved with a cleaning solvent and then blown dry with compressed air to remedy the issue, then the next best thing is to try and replace the tube socket itself to see if that will cure the static leakage.