Alright, this morning I rotated the engine again. The front rocker cover gaskets leaks, the rear leaks too. So this is not only PCV valve leakage. Crap!
I just can not trust those James gaskets anymore, they will leak again. So I decided to follow this thread and apply RTV silicone on lower gasket and Hylomar Blue on top gasket. Still do not know which RTV silicone is better to use. RTV black is the most oil resistant and has the best temperature resistance. RTV Blue is the suggested silicone for coating precut gaskets for increasing reliability.
