Ya, I would like a word for this as well. I naturally refer to this category of error as bug, but this occasionally leads to significant conflict with others at work. I now default to calling _almost everything_ a feature request, which is obviously dumb but less likely to get me into trouble. If there is a better word for "it does exactly what we planned, but what we planned was wrong" I would love to adopt it.
I reported such a bug to some software my company uses (Tempo). Vendor proceeds to call it a feature request because the software successfully fails to show public information (visible in the UI, but HTTP 403 in the API unless you're an admin).
Instead of changing one word in the code that defines the access level required for this GET call, it gets triaged as not being a bug, put on a backlog, and we never heard from it again obviously
