FWIW I don't think using WD40 is a good idea on O ring chains. (not that I don't think WD40 is good for other stuff).
It is a good solvent and mild lubricant. The solvent part is what I see as the problem. I think it can get behind the O ring seal and dilute the factory oil, which the O ring should keep in...and let the lub there dry up./then rust up. This is where most of the wear occurs. when we lube the chain we mainly lube the sprockets and the chain rollers. External lubing really does not get behind the O rings.
Keeping the O ring seals healthy and the oil behind them in-place is the main reason for cleaning