Somehow I missed a flight while I was at the gate. Mind you it was a small plane. I still don't understand it to this day. I was sitting at the gate waiting for them to announce boarding or watch the sign change. Nothing the whole time I was there.
Finally about 20 minutes after we were supposed to leave I get up and ask the desk staff and they tell me the plane left.
I didn't understand how this had happened and apparently neither did they. I didn't see anyone board the plane, there were no announcements or notifications.
You probably explained the unexplained. A gate change would explain why even the staff were confused, as they were just there for whatever other flight was assigned to that gate.