Commander William T. Riker: In your position it's important to ask yourself one question: what would Picard do?
Wesley Crusher: He'd listen to everyone's opinion and then make his own decision.
Capt. Picard: Tea, Earl Grey, hot.
Capt. Picard: Engage!
Lt. Cmdr. Data: If the warp drive fails to activate, the results could be... Unfortunate.
Lieutenant Worf: Very unfortunate. We will be dead.
Capt. Picard: Make it so.
Chosen answer: The uniform does indeed change colour. It may be due to the need for a green screen in part, or perhaps some lighting altering our perception. That being said, it certainly looks green at the start, blue thereafter.
The show has been done in HD now and not sure if they fix this problem.
Dan23