Shaco Thunerlord Bug [gameplay]

Hi: Playing Shaco with thunerlord's decree, I've seen many times when I deal damage with 3 sources of damage to the same target but thunderlord's is not triggered. For example hitting the q, then one autoattack and the E, but thunderlord doesn't go off. This happens with the active item of gunblade too. Please fix this as soon as possible. Also if I could get some rp or something for this that'd be awesome. : D