Oh my god, thank you. I've made a horrible mistake and overlooked checking "alpha" in the Render Settings "save" tab. Thank you!

I've been checking it in AE - no alpha. ¯\_(ツ)_/¯ I came across one or two other mentions of this problem on the internet, but haven't seen a follow up with a solution. Thought maybe I was missing something else that's obvious.

Alpha is enabled in kernels (like the Tehchriis' was, I believe) - that's what you were suggesting, no?

Same problem here. Did you figure it out?