The item OpacityMask seems internally to use a ShaderEffectSource which requires the property recursive to be set when it has a dependency on itself.

OpacityMask does not expose this property and it's possible to create such a dependency on itself. In this case one only gets an error message on std::out:

"QSGDefaultLayer::bind: ShaderEffectSource: 'recursive' must be set to true when rendering recursively."

This error message cannot be fixed with the provided API.