Sunder Hit detection issues

As the title suggests, I've been seeing some issues since launch with Sunder going _through_ enemies despite having 100% hit chance.

I wasn't recording so hopefully an image will suffice as some evidence:


Notice in the image the rocks underneath the enemy from sunder, and my 100% hit rate listed on the left, this happened multiple times on this one enemy.

My support gems are: Supercritical, Concentrated Effect, and Heavy Swing - the gem itself is a corrupted sunder gem with 10% quality.