Core-Plot crash only in Release Configuration

I really don't know a solution or even an idea to get around the following failure. It only happens in Release Configuration on the Device - Simulator and Debug Configuration work fine. It also only appears on the second launch. So if I have the phone connected to my mac, build the application and run it, everything works fine. If I then close the app and restart, it crashes. After long search, it seems that the error comes from the following line:

x.majorIntervalLength = CPDecimalFromFloat(2.0f); 

The code before:

               CPLayerHostingView *chartView = [[CPLayerHostingView 
alloc] initWithFrame:CGRectMake(0, 0, 320, 160)]; 
                [self addSubview:chartView]; 
                // create an CPXYGraph and host it inside the view 
                CPTheme *theme = [CPTheme themeNamed:kCPPlainWhiteTheme]; 
                CPXYGraph *graph = (CPXYGraph *)[theme newGraph]; 
                chartView.hostedLayer = graph; 
                graph.paddingLeft = 20.0; 
                graph.paddingTop = 10.0; 
                graph.paddingRight = 10.0; 
                graph.paddingBottom = 20.0; 
                CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)graph.defaultPlotSpace; 
                plotSpace.xRange = [CPPlotRange 
plotRangeWithLocation:CPDecimalFromFloat(0) 
                                     开发者_如何学Go                                                                      length:CPDecimalFromFloat(100)]; 
                plotSpace.yRange = [CPPlotRange 
plotRangeWithLocation:CPDecimalFromFloat(0) 
                                                                                                           length:CPDecimalFromFloat(10)]; 
                CPXYAxisSet *axisSet = (CPXYAxisSet *)graph.axisSet; 
                CPXYAxis *x = axisSet.xAxis; 
                x.majorIntervalLength = CPDecimalFromFloat(2.0f); 

If I comment the last line, everything works fine (off course the interval length is not correct). I would appreciate any help! Thanks in advance!

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Any chance CPXYAxis *x = axisSet.xAxis; is an x that is nil or not retained? It is not being checked for.