Alright
joey, I think I have fixed the file

I believe what was happening is your fire curve settings were making the bloom saturation and intensity go so high, it went negative. I have added every possible safeguard against it that I could think of and my testing shows the problem fixed under all conditions I could think of for bloom settings and fire settings.
I hope this new file works better for you. And don't forget if you aren't quite happy with the way it looks, there are a bunch of settings for the new bloom type, if you scroll down to where it says #ifdef CURVE_BLOOM. I think there are some comments to get you started. And be sure to try out sharp mode!
I am sorry for the initial mistake, I have a bad habit of never testing enough. Thanks for pointing this out to me, now I must update my own file!

edit: didn't see your post haha, anyway I would still recommend you use this new file because on my system I got a black looking fire with my curve bloom and the old file so there probably was some kind of issue somewhere.
edit 2: i am a bumbling idiot, sorry, forgot to attach file at first. Anyway of course you can use it in your preset, I would be so happy that someone is getting use out of something I did. Please post more screens when you get it how you want it!

Attachment:
enbeffect.fx