I reported this in-game and the rep told me to post it here. Basically, with Projected Textures enabled, some spells emit lighting effects on the ground, usually lines from the epicenter of the target. Others have reported it in the past, and I will list those below if the forums let me. Currently happens with Lightning Rod (Elemental Shaman) and WindShear. I have also seen it on an unknown warrior or paladin spell and some arcane orbs in the world.