Everything was going well initially - the people who interviewed me were courteous and helpful. I got through the technical interview and everyone seemed please with how things were going.
Then, they sent me a rejection email, which was fine, but then the HR person with whom I spoke to initially reached out a few hours later and told me the rejection email was a technical error and that they were actually interested in me. The HR person asked me if I was still interested, and I said yes. They told me they will reach out to me regarding next steps, and never did.
Initially, the company seemed OK, but the apparently false rejection and no-contact thing at the end makes them seem very unprofessional.