Earlier today, Dispatch revealed that G-Dragon failed to be promote Corporal, and he still remains Privet First Class.

But Military have released official reply, saying  Kwon Jiyong was supposed to be promoted on January 1st." however his promotion was delayed, but he expected to be promoted in March. 

They also stated "There is no such case where a person misses promotion due to so much vacation.If a person doesn’t pass the required tests for promotion (strength, physical fitness), then they’re omitted from promotions”