Objects in SpriteKit Game Stopped Colliding after iOS 7.1 update

Question

Objects in my spriteKit game stopped colliding after the iOS 7.1 update. This includes the bounds of the screen so the character just runs off screen. I'm using a bit mask to detect collisions and handling the collisions in the didBeginContact delegate method. I'll add the code for how I'm adding my SKNodes. Thanks in advance.

//main character 
self.girl = [SKSpriteNode spriteNodeWithImageNamed:@"pixelgirl"];
self.girl.position = CGPointMake(self.size.width / 2, self.size.height * 0.2);
[self addChild:self.girl];        
self.girl.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:self.girl.size.height / 4];
self.girl.physicsBody.dynamic = YES;
self.girl.physicsBody.affectedByGravity = NO;
self.girl.physicsBody.mass = 0.02;
self.girl.physicsBody.allowsRotation = NO;
self.girl.physicsBody.categoryBitMask = girlCategory;
self.girl.physicsBody.contactTestBitMask = tallTreeCategory | uglyTreeCategory | shortTreeCategory;

//contact object 
SKSpriteNode *pixelShort = [SKSpriteNode spriteNodeWithImageNamed:@"pixelshort"];
pixelShort.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:pixelShort.size.width / 2]; //2
pixelShort.physicsBody.dynamic = NO;
pixelShort.physicsBody.categoryBitMask = uglyTreeCategory;

- (void)didBeginContact:(SKPhysicsContact *)contact
{

__block BOOL isRotating;

[self performSelector:@selector(moveDog) withObject:Nil afterDelay:.3];

isRotating = NO;

if (!isRotating) {
    SKAction* action0 = [SKAction scaleXTo:1.0 duration:0.05];
    SKAction* action1 = [SKAction scaleXTo:0.1 duration:0.05];
    SKAction* action2 = [SKAction scaleXTo:-0.1 duration:0.05];
    SKAction* action3 = [SKAction scaleXTo:-1.0 duration:0.05];

    SKAction* action = [SKAction sequence:@[action0,action1,action2, action3]];

    [self.girl runAction:action completion:^{
        isRotating = YES;
    }];

    }

}

Answer 1

Your problem is scaleXTo:-1.0. I used the exact same command to mirror one of my sprites and as soon as I did, the little guy stopped responding to ALL contacts. Remove it and all be well again.