Three butlers taking turns

Not sure if this is a bug, so I'm posting it here.

I currently have a household of 7 people and one pet, and a butler. Whenever I travel with one or some more sims of the household for a day to the beach or to my restaurant, not only am I always meeting my butler there as a restaurant visitor or a person at the beach, when I come home a butler comes running. And most of the time it is not my butler.

When I played the restaurant daily, I had three butlers taking turns running towards my house when I came home in the evening. I wouldn't bother too much if I wouldn't have to assign the bed each time. As you can't assign the bed to whatever butler you happen to have that day, you have to choose a sim. Which is nonsense as you can't have more than one butler (as far as I know).

Is this a bug?