感覺這個(gè)問(wèn)題問(wèn)的非常的好，我也沒(méi)注意過(guò)這個(gè)細(xì)節(jié)!
正如樓主所理解的，我們知道TAU是EMM的過(guò)程，所以在ESM連接時(shí)，是不會(huì)有TAU過(guò)程的，正如3G的RAU。
我們看TAU過(guò)程章節(jié)可以看到，只有在異系統(tǒng)切換時(shí)，說(shuō)需要進(jìn)行TAU，但并沒(méi)有樓主所述的

我們?cè)偃タ碋SM章節(jié)介紹，可以看到與RAU不同之處，當(dāng)TAI變化時(shí)，需要進(jìn)行TAU過(guò)程也就是樓主所看到的過(guò)程，這個(gè)時(shí)候ESM需要重新初始話
If lower layers indicate a TAI change, but the current TAI is not in the TAI list, the ESM procedure shall be aborted and re-initiated after successfully performing a tracking area updating procedure.

If lower layers indicate a TAI change, but the current TAI is still part of the TAI list, it is up to the UE implementation how the ESM procedure is re-initiated.

If lower layers indicate the TAI has not changed, it is up to the UE implementation how the ESM procedure is re-initiated.

NOTE 1: The ESM procedure can typically be re-initiated using a retransmission mechanism of the uplink message (the one that has previously failed to be transmitted) with new sequence number