In this scenario:
If the UE indicates support for dual connectivity with NR in the Attach Request / Tracking Area Update Request Message, and the MME decides to restrict the use of dual connectivity with NR for the UE, then the MME set the RestrictDCNR bit to “Use of dual connectivity with NR is restricted” in the EPS network feature support IE of the Attach Accept / Tracking Area Update Accept Message.
Here UE indicates support of ENDC in attach request. Bu here also MME sets RestrictDCNR. Why?