Hextech Protobelt-01, Glacial Augment, and Rylia's Crystal Scepter.

So why doesn't Glacial Augment path slow proc on a Hextech Protobelt-01 with Rylia's Crystal Scepter adding a slow to it again?

It's not like 10% slow is OMFG WOW vs . Also, you are still using an item so...