"It was violated almost immediately" is the right answer.
Self-determination was a secret talking of president Wilson and the ideas behind the League of Nations. The principle of self- determination, often regarded as a moral or constitutional right is that each country is authorized to have a sovereign territorial state in which every identifiable community would decide the state with which they belong.
It was violated because not all the citizens got a country, and when the boundaries of nations were being rearranged many groups of people were forced to remain in different countries. Hence, it was violated almost immediately.