Jus isn't gravy. Using jus for jus is merely accurate. Using jus for gravy is incorrect, not necessarily (but probably) pretentious.

A medley is a medley. Overcooking it doesn't make it not a medley.

What you're complaining about, Steve, doesn't seem to be the words themselves, but that bad cooks use them.

That's a cooking peeve, rather than a language one.

Yesterday's menu said Red wine reduction. I got brown gravy. Not pretentious, but bad cooking.