In these cases, did the household have a partial or full ownership of the rabbit hole where your sim worked?
I had that happen once, when I was playing the Landgraabs, and I also had NRaas Story Progression running. I noticed that Geoffrey had Nancy as his boss, which made no sense because she was in the business career. However, the household had purchased a partnership in the hospital. Since there were no sims higher than Geoffrey in the career, I figured that it just picked one of the owners that wasn't him to be his new boss. Later on, I also noticed that Geoffrey was her boss when she was the highest in the business career and they also partly owned the Doo Peas towers.