My son is just the same as you, also 14 months age. He suddenly refuse to eat congee but willing to drink milk. Energetic and looks happy, everythings all right.
It last for about half months starting from early Sept. I try to feed him different tasty food, he improves a lot. I've ask some of my friends, they said when baby gets around one year old, they learns how to refuse things including food, and wants different taste.