Shen - Q enhanced attack not working if Spirit sword doesn't move.
I haven't tested this completely but it appears to be that if Shen's spirit sword doesn't move when Q is pressed, Shen does not gain the effects of his enhanced Q nor does his passive shield proc. This can especially make jungle rather irritating at the start if you forget to move in between your slowish clear speeds.
Q goes on cool down. Shen does not gain the enhanced attack buff. Passive does not proc. Likely cause - Sword doesn't move (if cast on top of where the sword already is)