Sometimes what is a glaring error to us, is not noticed at all by the person we made it for. I've had that happen and have wondered what the heck's the matter with their eyes. But we know what to look for and really, no one else (who doesn't quilt) does. Put it out of your sight for a short while, then take it out and toss it on a bed and look at it again. Bet you will have to search to see the mistake even though it's a big one.
I feel for you. Been there, done that. :-(