Windseeker's says it doesn't work on yourself in-game, but mentions nothing about it in-client

In-client it says "Your heals and shields are 10% stronger. Additionally, your shields and heals increase your target's resistances by 15% for 3 seconds when used on an ally other than yourself."

It makes it sound as if the first sentence applies to you, while it really doesn't. It is a bit misleading, I'll give you that.