Drenched+Shock Conduction II does not work with Siphoning Strike

Hello,

I tested quarterstaff auto attack with Shock Conduction II (no lightning dmg component) and it does shock drenched target every strike.

Drenched+Shock Conduction does not make Siphoning Strike shock. Not before or after shock check for power charge generation.
Siphoning Strike has nothing in description that says it cannot shock.