hi ranat,
It sounds to me as if your describing water on your plate after the sauce has sat on rice or chips for a little while, the water in the sauce can start to drop out of the sauce if you follow me,
this is usually remedied by cooking your sauce a little longer to reduce the water quantity in the sauce a little more,,
If this is what you describe then the same can happen in chillies or spag boll sauce,
Bob