Logs "finished = 0" When I remove the changes in the animations block, finished = 1 The changes are applied, but immediately. Duration = 0.3 but setting any value does not matter.

Animations.m

        _blurView.alpha = 0;
        CGAffineTransform toTransform = _snapshotView.transform;
        _snapshotView.transform = CGAffineTransformIdentity;

        [UIView animateWithDuration:[self transitionDuration:transitionContext]
                              delay:0
             usingSpringWithDamping:0.8
              initialSpringVelocity:0.2
                            options:UIViewAnimationOptionCurveEaseOut
                         animations:^{
                             _blurView.alpha = 1;
                             _snapshotView.transform = toTransform;
                         } completion:^(BOOL finished) {
                             NSLog(@"finished = %d", finished);
                             [transitionContext completeTransition:YES];
                         }];