I had this same problem with the water pump operator from one of my games. They would stay in their house all day causing the water pump to remain empty, until my settlement died of thirst. It would not happen all the time, but when it did it was catastrophic if I didn't have backup drinking stations. I was also playing Eager Beavers at the time. Not sure if it was happening with any other beavers, I just took notice of the water pump operator since it was causing my beavers to die from thirst. Save attached is from after I installed two backup drinking stations.
EDIT: Should also mention I was playing on a custom map downloaded from the Discord server.
Autosave 2020-01-05 22h19m, Day 97.json Player.log