I find some of these issues do pop up as the child gets older and the dynamics in care change. She needs to be reminded that the other kids lived through the crying and adjusting her baby did and now it is payback time sort of thing.
I am also wondering what else is going on in her life. When a parent suddenly turns full circle like that there is often a reason - something going on at work, home, wider family issues. You might want to pursue that avenue and come right and ask her commenting that you are confused by her sudden change in attitude towards your daycare ( make it about daycare and not about you) and are wondering if there is somthing going on that is causing her additional stress and if there is anything you can do to help...that is when we find out things like parents are separated, grandparent had a heart attack or diagnosed with cancer, having financial problems, etc.