I was asked to respond to a list of questions via email. Next step of phone interview was missed by the interviewer. I emailed after waiting 30 minutes, and it took them until mid afternoon on the next business day to reply. We rescheduled (they offered a Sunday, which seemed like a bad sign about company culture and work life balance on weekends), there was no explanation of the missed appointment, and a very cursory apology at the end of the fifteen minute call.
I was relieved not to advance to the next round of interviews or to get an offer - I imagine whoever is in the role will be apologizing for colleagues missing appointments or having to reschedule meetings regularly!