Hi MrsKK *waving, I know you from KFC.
Nitai, Are you mixing her milk with the jersey milk from a cow that is drying off? Did I understand that right? You might consider the "drying off" cow could be part of the problem. When my girl starts to dry off, everything goes off. My butter won't break, cheese won't set and milk doesn't last as long.
I don't know if that's your case, but could be something to consider.