Fervour of battle not stacking with illaoi while auto attacking a pulled out spirit

So on illaoi her test of spirit(her e ability) storm raiders surge,Warlords blood lust,thunder lords decree,death fire touch I believe,and grasp of undying will proc on the spirit,but for some reason fervor of battle will not proc while auto attacking the spirit. Is it a bug or is it supposed to be intended like that? I believe the current fervor would be pretty strong on her due to the scaling her tentacles have with high ad and the auto attack reset her harsh lesson(her w) has if it worked on the spirit.