[GAMEPLAY] Singed fling not rooting ulting Master Yi

This happens anytime a Singed flings an ulted Master Yi into his Mega Adhesive.

To reproduce this simply grab a Master Yi and have him ult. Then, have the Singed place the goo behind the Singed and fling the ulted Master Yi into the goo. It will not root him even though Master Yi is not resistant to roots.

I encountered this interaction in a ranked game earlier and I was wondering why I wasn't rooting the Master Yi. I then asked him to test it with me and he generously allowed me to do it, as seen in the Plays.TV link I linked. Basically, the Singed would place the Mega Adhesive behind him and then fling the ulted Master Yi into the goo and he would not get rooted. I do not know if this is intentional or not but the text on the root in Singed's kit says nothing about the target having to be slowed by mega adhesive to be rooted by the WE combo. If this intentional, an update to the text on the ability would be useful, but if it isn't intentional, this would save me many deaths in games. Thanks!

EDIT: It happened again in my latest ranked game. Rito pls fix/update text