still the problem here, only evade if you make map quest first and then trigger the milk quest. the bug is when you trigger milk quest before a map chain o trigger both in same time.
so.....if any trigger the milk try ignore the farm, make the map quest and this trigger milk again in shop second time, then go to farm.
you need: teddy bear for litte sis so go shop and wait the bear, then little sis say the map is in big sis room, family breakfast face big sis for open she room for milk, then go shop, then go farm, return home, breakfast family and put the milk in the bitch sis, after all this in order. Save the game and try give milk to debbie.