3GPP 24.501 v20.0.0 — the document's own text

5.2.2.1 General

Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).

The state 5GMM-DEREGISTERED is entered in the UE, when:

the de-registration is performed either by the UE or by the network (see clause 5.5.2);
the registration request is rejected by the AMF (see clause 5.5.1.2.5 and 5.5.1.3.5);
the service request is rejected by the AMF (see clause 5.6.1);
the UE is switched on; or
the UE registered for emergency services is in 5GMM-IDLE mode and its periodic registration update timer expires (see clause 5.3.7).

In state 5GMM-DEREGISTERED, the UE shall behave according to the substate as explained in clause 5.2.2.3.