iOS - completion block in UIView animateWithDuration gets called too early

I'm trying to do some animation when a table view cell gets selected. For some reason, the completion block is getting called way too early. Even setting the duration to 10 seconds, the completion block gets called immediately.

[UIView animateWithDuration:10.0 animations:^{
    message.frame = newFrame;
} completion:^(BOOL finished) {
    NSLog(@"DONE???");
}];

Any thoughts on why this is happening? Thanks.