Brief phone conversation with someone in HR, then in-person interviews set up by video (before the COVID-19 pandemic hit).
Red Flag #1: One interviewer was calling in by video despite the fact that she was in her office down the hall the entire time (first red flag).
Red Flag #2: The condescending looks one inexperienced, young interviewer (no idea why he was there to begin with) kept giving other interviewers - this was deeply unprofessional.
Red Flag #3: Their confusion around expectations for the role - their line of questioning convinced me that I would be very frustrated in the position, because they didn't seem to have a concrete idea of what it is they wanted.
Red Flag #4: They also seemed to be unnecessarily snobby when I asked relevant questions about how their approach to new and developing situations critical for this role, so I got the impression that they must be doing God's work.