Ergativity Question

I'm pretty sure I understand the basics of what an ergative/absolutive
language is (as opposed to a nominative/accusative one), but I've got a
question. Would it make sense for a language to be ergative/absolutive in
the passive voice, but nominative/accusative in the active voice? Are there
any example natlangs or conlangs that do this? It's one possible system I'm
considering for Akathanu (which is kinda funny, considering that Akathanu
doesn't even really have verbs, except an extended form of the copula).

Thanks,
~Caleb