Windwall Interaction With Vel'Koz E

Although Tectonic Disruption is a ground-targeted skill, Windwall still blocks it.

I've always been pretty iffy about whether or not it SHOULD actually be blocked. Ground targeted skill would imply it shouldn't but at the same time it's considered a projectile because it "originates from Vel'Koz's tentacle".

Now, in a recent game, I've got a whole different problem... The skill has already been cast, so why does Yasuo placing his windwall on the circle cancel the entire skill?

Is it possible to fix this?