So, there was something I noticed while doing Ur on Uranus and it has something to do with Saryn's Venom Dose augment. It seems that it allows you to cast (or recast) the buff for 0 energy. This is only the buff, since it won't allow you to cast Spores due to the lack of energy. First I thought it was just a one time bug, something on Ur, but I went and checked in the Simulacrum and indeed, you can buff yourself for 0 energy drain. Casting it while you still have energy will drain 25 as normal, but when at 0, you can cast it for no cost. And the buff is applied as normal. I checked on my Oberon (since that's the only other one of buffing augments I currently have), and it doesn't allow you to cast Smite infusion on yourself when you're out of energy. Not sure for the other ones, but Saryn's seems to be bugged.