Twice during my gameplay today, I noticed that after drinking the Flaming Humbaba, which grants 0 energy drain while refining ore for the duration of the buff, the buff never actually disappeared from my hud. On top of which I was still being granted the 0 energy cost bonus. I also had this happen once with spinach (though somewhat regrettably not during the Rook's Crusher Quest :p ). I wasn't able to reproduce this 'glitch' at will, but I think it may be related to lag as I am certain that during at least two of the instances I ate/drank the items I was experiencing heavy lag with the occasional momentary disconnect.
In all three cases a simple browser refresh fixed the issue of the perma buff.