Illaoi/jax interaction bug

I was playing just now as illaoi when i realized that while jax had his E active/dodging, if I ulted him during this time he would dodge it completely and I wouldn't spawn a tentacle. This is a huge bug that almost cost me the game due to not being able to split anymore due to jax just dodging all my damage and killing me with ease. I really don't think this is intended, because illaois ult is definitely not an auto attack.... jax shouldn't be able to dodge it.