My interim manager has referred to their role as baby sitting. And this irritates me as it feels dismissive of me and the other person in our team. What's worse is the new permanent manager has joined and is using it as well... "(name) has been babysitting the area" like this is now an OK verb. Maybe I am being over sensitive, but it really grates on me.
If I was you I'd pretend I'd not heard them correctly and ask them to repeat themselves, and if they said 'babysitting' again I'd act all dim and look around confused (as though expecting to see real babies) saying "What do you mean?" to see what their explanation would be.