REC/RPL Compliancy Definition

I wanted to use the REC/RPL tool in a project. But compliancy definition are not very clear for me.
A black box compliancy seems to ensure when you run a model validation that a RPL is strictly identical to its REC (same interfaces, same internal elements,…).
I activated the validation rules and tick “Enforce RPL Compliance On the Fly” on the Replicable Element REC.
I tried to add a internal element to the RPL (image 1).
When I run a model validation, this doesn’t display any errors concerning this point. Moreover, you can modify the RPL element as you want without errors.
Is it mean to occur?