Weather Effects and Invisibility?

I noticed this last night while playing against a Phantom Lancer. I have my three custom weather effects on shuffle, so each game gets one of the three. Well, in this game it was rain and I noticed something kind of odd. We had just engaged PL by the river between the two mid towers, up on the Dire side. He was all alone and a couple of us were closing in, so he naturally Dopplewalked out. We instantly killed the illusion, so there should be absolutely no trace of the real PL anywhere. However, I noticed the ground having some strange movement and realized that it was footprints being left by PL in the rain. Every hero makes a little splash with their feet when walking through it, but I think they forgot to remove it for invisibility. It didn't matter where PL went, I could easily track him down just by watching where his feet were, which kind of rendered his skill useless. Obviously, everyone wasn't using rain, so they didn't have the same advantage I did. Thoughts?

NEW META

That heppens with with Batriders Napalm at DotA from W3 as well, but every one could see the oiled body but they wasn't able to click on him.

Yeah, I know invisibility gets messed with by some abilities and gives pseudo-vision. But this is a weather effect that not everyone is using, meaning that some players have the advantage while others don't. Definitely needs to be fixed.

Be happy and rape Riki before they patch it.