Don't know when it started, but just noticed it. I suspect it has been that way since we have been limited to 3 auras. Once you have all 3 auras up, it takes up the entire heat bar. Same Auras, Same Runes and I know the auras affect the reserved heat. But they seem to be taking up more heat, than they were before the patch. 3 of the auras I use are now taking up the same heat as 4 auras from before.