W.C.
At age four there is often another separation anxiety for some kids. Also girls this age get very attached to their daddies. It is a phase and it will pass. The cure is just to live through it. I know that doesn't help much.
Maybe she can begin to draw daddy a diary of her day when he leaves to help that separation anxiety. Start the minute she begins to cry to take her mind off the crying.
Or have her choose the books that she wants daddy to read her that night the minute she begins to cry.
Or say to her, okay you can cry for 5 minutes, and then set the timer. When it goes off, say okay, times up! no more crying! And then start the diary.
The thing is to get her busy and get her mind off the leaving and onto something else.