Pantheon bug interaction with Morgana black shield

I was playing a game against a heavy ap comp as jg pantheon, but morgana kept overextending in my jg for some reason. so whenever i jumped on her with my W, her black shield negated the stun, which is fine, but then it nullified my Q, and my E. at first i thought i had just missed the skill shots, but after having several kills on other champs, i started to notice she would black shield whoever i jumped on, and my Q wouldnt damage them either, or anyone for that matter with black shield. The bug is black shield cancels Pantheons Q and E as if it were a spell instead of physical dmg.. i saved the replay and hopefully i can look into it further...but i cant explain it...