Solarsplace, thanks for trying it. I'm not sure what you mean by tang, to me it means something like that which would be imparted to a dish by the addition of lemon, for example. If so it shouldn't have any tang to it at all.
This should particularly not be the case if you also added the cream.
It could be that the 'tang' is in fact the asafoetida, if you're not used to it, but that usually imparts an onion/garlic type of flavour. And there's a good deal of difference in adding asafoetida in its natural resinous state (usually bought as a little rock) and the powders normally available which are quite heavily adulterated with other things like turmeric and thickening powders, so that might make a difference too.
So was the 'tang' pleasant or unpleasant?
BTW, if you use lamb you should replace the chicken stock cube with lamb stock cube (hopefully totally obvious, but I never explicitly mentioned it before).