I think this is an expected behavior because, Model Reference block is a reference to another model. And the 'Goto' tag being defined in current model, cannot be visible in the other model which is referred by Model Reference block.
Setting the 'Goto' tag visibility to 'global' will make it visible across different 'Subsystems' which are present in the current model, but it won't make it visible to a different model which is referred by a 'Model Reference'.
You can read about the tag visibility more in the following documentation link:
