3GPP 24.501 v20.0.0 — the document's own text
8.3.8.2 Back-off timer value
Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).
The network may include this IE if the 5GSM cause is not #26 "insufficient resources", #37 "5GS QoS not accepted", #44 "Semantic errors in packet filter(s)", #45 "Syntactical error in packet filter(s)", #46 "out of LADN service area", #59 "unsupported 5QI value", #67 "insufficient resources for specific slice and DNN", #69 "insufficient resources for specific slice", #83 "Semantic error in the QoS operation", #84 "Syntactical error in the QoS operation" or #87 "QoS differentiation for non-3GPP device identifier(s) not available" to request a minimum time interval before procedure retry is allowed.