[defphysics]

Actually, what you're describing sounds like something you'd refer to as "not a showstopper". To me, a "showstopper" is something that stops the show: that can't be ignored or "fixed later".

[hamburglar]

Yes. “We were planning to launch tomorrow but someone found a showstopper so we are on a day-for-day slip” is how I’d use it in a sentence.