This has been solved. I found it's caused by the return value of outputShapesForInputShapes not matching MLCustomLayer protocol. Now i have resolved it. Thanks!

You run the custom model by Objective-C++ implementation? I try to do this but get some error as i described in https://developer.apple.com/forums/thread/698611. The MLCustomLayer protocol including evaluateOnCPUWithInputs initWithParameterDictionary outputShapesForInputShapes setWeightData are implemented. But it still can't work. Are there any special settings in your project? Any idea on help this would be grateful. Thank you!