Very odd; no unusual moodlets or anything popping up on your Sim as a result of the sudden thought bubble?
When they got up to take care of the Toddler, was it because the Toddler was crying or making some sort of commotion? (I ask this one since I've seen Sims get up to take care of babies, but it usually doesn't generate a thought bubble like that.)
Has this happened to any other Sims you've worked with?
- B