I had that problem lot. It frustrated the heck out of me, so I added a couple of triggers to EDCT. Now, Augustus is named every time the previous Augustus dies.
Code:
;------------------------------------------
Trigger Augustus_Named_Backup
WhenToTest CharacterTurnStart
Condition IsFactionLeader
and SettlementBuildingExists = romani4
and EndedInSettlement
and FactionType seleucid
Affects Augustus 2 Chance 100
Affects Augustus 2 Chance 100
;------------------------------------------
Trigger Caesar_Gets_Augustus_Label
WhenToTest CharacterTurnStart
Condition IsFactionLeader
and Trait Caesar > 0
Affects Augustus 2 Chance 100
I suspect it has to do with Augustus being an antitrait for Caesar. When the Caesar becomes faction leader, it wipes out the Caesar trait, but does not install the Augustus trait. Hope that helps.
Thanks,
ADM