"Je suis un autre."
Asking native French speakers, would "Je suis un autre," ever mean the sense of, "I am another (person who fits some previously mentioned description)", or does it always mean, "I am an other (i.e., I am identified by not being a member of the group in whose company I habitually find myself)"? Duolingo doesn't like that I didn't put a space, and I'm fairly sure it's just because they're missing an alternate, but since the two sentences have subtly different meanings I wanted to make sure.
Actually, I don't think of any context when we would say "je suis un autre", because it is vague. I would say "je suis quelqu'un d'autre" (meaning I was mistakingly taken for someone else) or "je suis une autre personne" (same meaning) or "je suis différent" (from the lot).