iOS 8 SpriteKit rendering issues - ios8

Question

Upon testing my app in iOS 8, I ran into some serious rendering issues. Instead of wasting text trying to write a comprehensible description, I'll just show you a short video:
This is what it's supposed to work like. iOS 7.
And this is how it breaks in iOS 8.
A slight breakdown of what you saw: The tiles zooming in is an SKAction running on each tile individually. The tiles spawn with an alpha of 0 with the SKAction fading them in, one at a time. If I spawn the tiles with an alpha of 1.0, they show up, but don't perform any action. Other actions randomly don't run either. So there at least appears to be some issue with SKAction. I cannot figure out what's making the rest of the scene disappear when a new round occurs, though. There are no SKActions relating to those nodes or textures at all.
Does anyone know if there are new limits or issues with SpriteKit in iOS 8? Especially relating to SKAction it seems, but anything that might relate to this at all?
Edit: I just want to clarify that even though the video for iOS 8 is the simulator, I've had a report from a beta tester of a problem of this exact description on a real iOS 8 device. The iOS 7 video is a screen capture from my own iOS 7 device.
Edit: here's some code relating to this:
-(void)startNewRoundWithGridSize:(CGFloat)newGridSize andWormCount:(NSInteger)wormCount{
gameData.currentWormScore = (int)currentRound;
[gameData checkAchievements];
previousRandomShake = sharedUtilities.currentTime + 10;
[self randomizeShakeType];
if (gameData.isComputer || gameData.isPhone5) {
directionImage.position = wormDirectionPhone5GamePos;
} else if (gameData.isPhone4) {
directionImage.position = wormDirectionPhone4GamePos;
} else if (gameData.isPad) {
directionImage.position = wormDirectionPadGamePos;
}
directionImage.hidden = VISIBLE;
[directionImage setScale:0.33];
roundCounter.hidden = VISIBLE;
timerBar.hidden = VISIBLE;
int additionalTime = [settingsDict[#"subsequentRoundTimerPoints"] integerValue] + 0.5 * timerValue;
if (currentRound == 1) {
timerValue = [settingsDict[#"firstRoundTimerPoints"] integerValue];
} else {
timerValue = additionalTime;
}
if (gameData.godMode) {
timerValue = 600000000;
}
gridSize = newGridSize;
if (gameData.isPhone4 || gameData.isPhone5 || gameData.isComputer) {
tileBaseSize = 80;
} else if (gameData.isPad) {
tileBaseSize = 192;
}
roundCounter.intValue = currentRound;
SKNode* oldWorld = [self childNodeWithName:#"wormWorld"];
if (oldWorld.parent) {
[oldWorld removeFromParent];
}
[startButton disableButton];
[backButton disableButton];
[instructionsButton disableButton];
startButton.hidden = HIDDEN;
backButton.hidden = HIDDEN;
instructionsButton.hidden = HIDDEN;
wormArray = nil;
wormArray = [[NSMutableArray alloc] init];
tilesArray = nil;
tilesArray = [[NSMutableArray alloc] init];
SKSpriteNode* alphaNode = [SKSpriteNode spriteNodeWithColor:[SKColor whiteColor] size:CGSizeMake(self.size.width, self.size.width)];
alphaNode.anchorPoint = CGPointZero;
alphaNode.position = CGPointMake(0, 0);
CGFloat worldYPos = (self.size.height - self.size.width) / 2 ;
SKCropNode* wormWorld = [SKCropNode node];
wormWorld.position = CGPointMake(0, worldYPos);
wormWorld.name = #"wormWorld";
wormWorld.maskNode = alphaNode;
wormWorld.zPosition = zGameLayer;
[self addChild:wormWorld];
SKSpriteNode* wormAreaBackground = [SKSpriteNode spriteNodeWithColor:[SKColor colorWithRed:0 green:0 blue:0 alpha:0.45] size:CGSizeMake(self.size.width, self.size.width)];
wormAreaBackground.anchorPoint = CGPointZero;
wormAreaBackground.name = #"wormAreaBackground";
wormAreaBackground.zPosition = 0;
[wormWorld addChild:wormAreaBackground];
SKNode* wormScaler = [SKNode node];
wormScaler.name = #"wormScaler";
wormScaler.xScale = 4 / gridSize;
wormScaler.yScale = 4 / gridSize;
wormScaler.zPosition = 1;
[wormWorld addChild:wormScaler];
//tiles
CGFloat totalDuration = 1;
CGFloat duration = 0.15;
SKAction* tileScaleIn = [SKAction sequence:#[
[SKAction scaleTo:5 duration:0],
[SKAction scaleXTo:1.0f y:1.0f duration:0.1],
]];
SKAction* tileFadeIn;
if (gameData.debugMode) {
tileFadeIn = [SKAction fadeAlphaTo:0.5f duration:duration];
} else {
tileFadeIn = [SKAction fadeAlphaTo:1.0f duration:duration];
}
SKAction* tileAnimation = [SKAction group:#[
tileScaleIn,
tileFadeIn,
]];
for (int i = 0; i < gridSize; i++) {
int y = i * tileBaseSize + 0.5 * tileBaseSize; //start new row of tiles and set y pos
for (int h = 0; h < gridSize; h++) {
int x = h * tileBaseSize + 0.5 * tileBaseSize; //set x of current tile
SGG_TileNode* tile = [SGG_TileNode node];
if (gameData.debugMode) {
tile.debugMode = YES;
}
tile.position = CGPointMake(x, y);
tile.gridSize = CGSizeMake(gridSize, gridSize);
tile.tileIndex = i * gridSize + h;
tile.name = #"tile";
tile.zPosition = zGameLayer + 15;
tile.alpha = 0.0;
[wormScaler addChild:tile];
[tilesArray addObject:tile];
SKAction* waitABit = [SKAction waitForDuration:((totalDuration - 0.2) / (gridSize * gridSize)) * tile.tileIndex];
SKAction* totalAction = [SKAction sequence:#[
waitABit,
tileAnimation,
]];
[tile runAction:totalAction withKey:#"startingZoom"];
}
}
gameStarting = YES;
}
I know it's rather long. :(
Edit: Okay, upon some further testing, (in iOS 8 and 8.1) I've added an SKAction to the scene before the game gets started. It works fine until the game starts, but once it starts, the action just stops. Once again, this only happens in iOS 8+ and not iOS 7. Is there some limitation on the number of SKActions that can run simultaneously or something? Do SKActions stop when reaching some sort of memory limit (that would include art assets and other objects in memory)? And if it is, why would it only affect iOS 8+? And no, I'm not pausing the scene by accident. To be absolutely sure, I added
self.paused = NO;
To the update method to be certain the game isn't paused.