If it can be arranged, it would be useful for a while for the father not to participate in the dropping off of the child (picking up would be OK), and in general for him not to be in the day care space. As you know from having done the kind of work you do, most children with such
separationPlacenta abruptio
Separation anxiety anxiety adapt after a while. A few do not, and are not quite ready to be away from parents. It would be best to try to stick it out, though, because soon she'll be of kidergarten age and will need to be away from her folks.