@Rioters question How exactly does the new Runeglaive works.

As, from testing It seems it makes all auto attack modifiers such as Rengar q, Gankplank q, and Ezereal q makes the auto attack do 100 percent magic damage instead of having the appropriate physical damage then add the extra magic damage. Why exactly does this happen and is this intentional? Thank you for reading and taking time to answer possibly.