The interface is designed to disable the proxy resolution of the InverseCrossReferencer.

This capability is typically used to prevent loading a resource during its unloading.

Furthermore, it is not recommended to add other ECrossReferenceAdapter additionally to those created by Sirius. Note that you can get the semantic CrossReferencer with

However, in the case where an additional custom ECrossReferenceAdapter is needed, it should extend or at least implement SiriusCrossReferenceAdapter with the same implementation as SiriusCrossReferenceAdapterImpl.
Otherwise, there is no guarantee that load during unload won’t come up.