Um, that was me. Extensive and profuse apologies are offered to any who were upset- it was my first fill and I wasn't even aware there was a cannibalism tag, and it just didn't occur to me that the vengeance might trigger or even need a warning- dunno what that says about me (maybe I just read too much horror fiction).
Explanations/excuses aside, sorry about that, really. And I don't want to be presumptuous, but as you said you were unsure about reporting it- don't feel bad about reporting this on my behalf- it's the only way I'll learn these things that slip my notice, and I don't want anyone to be triggered by my writing.
Sorry for the extra work caused to the mods, sorry to any who were upset, and I will be more vigilant in future.
Again, apologies.