I'm playing an eldritch knight right now and was super excited to finally upgrade my dragon breath into the energy vortex. So I grab the upgrade and start slaying monsters. After a while I notice that my Vortex is doing nothing... Definitely not a good experience.
Anyway, I wonder off to searing heights to do some testing. When just activating the strike I was unable to do any damage to anything.
However, if I hard-target a mob first and then activate it that single mob takes double dragon breath damage (this works even if they are outside the range of the character centred aura) and then the vortex will proc as per the description doing the base dragon breath damage to things around you.
Hopefully this helps people until a fix is made for this spell to behave as per the description.
Also, how do I check my DC for my dragon breath? Spells have their DC in the tooltip but the dragon breath doesn't.