Just want to add the information.
I have found the same case for this and as per traces the process will be stop post first attach request verification, in this point Core will inform UE that EPS network feature RestrictDCNR bit to “use of dual connectivity with NR is restricted”
2nd related DCNR. In this case DCNR should be mentioned as “1” bit , please noted some mobile sent bit 1 but some mobile 5G supported doesn’t provided the DCNR bit clearly but it represented under octet 9 information as long as octet 9 was sent from UE to NW so NW able to identified that handset supported the 5G tech.(it was tested on ZTE mobile)
Basically Octet 9 always broadcasted under 5G handset information, we can see from Xcap analyses,
Normal octet 9 information. With or without bit 5 it doesn’t have any issue.
Bit 1- Multiple DRB
Bit 2- V2X PC5
Bit 3- RestrictEC
Bit 4- CP Backoff
Bit 5 - DCNR
Bit 6- N1 mode
Bit 7- SCG
Bit 8- 15 bearers.
So don’t confused if DCNR is not available but while octet 9 is available so we can said that mobile is 5G capable here.
Process stop on this step while 5G is not provisioned.