The Chicken Korma recipe that I've been making always seems to separate near the end of preparation. This ranges from small lumps forming too yellow water raising to the surface.  I read through the advice at How do I prevent coconut milk from separating in Thai curry? and was careful to keep a low simmer.  The recipe is basically:   Fry butter, onions & spices in stages Add cubed chicken breasts and let fry Add 1 cup tap water (perhaps the culprit?) and plain yogurt (not low fat) let fry Add 1 can 2% Condensed Milk reduce heat and simmer   I'm using a coated steel wok on a large element. For steps 1-3 I use just over medium heat and switch to medium-low, low for 4. After 2-3 minutes, the sauce starts to break. 
Still tasty implicitly says that the sauce stays indefinitely technically edible. The expiration date is only for quality purposes. I think the sauce probably doesn't have an expiration date but rather a "Best By" or "Best if Used By" date.        Storage time shown is for best quality only — after that, the sauce's texture, color or flavor may change, but in most cases, it   will still be safe to consume if it has been stored properly.   If sauce develops an off odor, flavor or appearance, it should be discarded for quality purposes.     