3GPP 24.501 v20.0.0 — the document's own text
7.5.2 5GS mobility management
Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).
No exceptional cases are described for 5GS mobility management messages.
No semantical or syntactical diagnosis other than presence and length shall be performed on the EPS NAS message container information element in the REGISTRATION REQUEST message.