I have gotten this research before. I don't know that it is a bug, the autopsy techs seem to be generated from combat rather than only lifepods under-the-hood.
For this specific case it can make sense to generate the autopsy tech since you would presumably be able to autopsy their ground units or the remains of the ship crew after a boarding action, even if you don't capture any lifepods. Practically, all the autopsy techs give you is the biological stats on the alien race (i.e. the factors for colonization cost, gravity, temperature, pressure tolerances and so on) so it's not exactly problematic for the game.