It doesn't happen very often, but occasionally a WE trigger will get stuck and not spawn the next encounter like it should even though the previous one has shut down. I've been trying to figure out what causes it but haven't been successful so far. There's a possibility it's related to a few specific world encounters, but I haven't been able to find any definitive proof of that. I should note that the WE spawn point isn't "broken" for the rest of the game, but you have to stay away for 10 in-game days for it to "fix" itself, which is obviously not normal. The same thing happened to the spawn points way back when certain WEs weren't unloading due to having the "run once" flag. The difference here is that the previous encounter reaches stage 255 (its shut down stage).
WE04 (Dragon vs Player) is one that I think "may" cause the problem; it was the last WE before the trigger box quit working in at least two cases. DLC1WE05 (Vampire and Death Hounds) is another where it happened at least once. One theory I have is that the encounter related NPC(s) get too far away from their original spawn point. Again, it may just be a coincidence that (I think) these two may be responsible. It's possible that there's something else going on.
Using sv on the trigger box's reference doesn't show any obvious problem from the output, as far as I can tell (but I have pasted the output in the spoiler below). In this case, the broken trigger box is 9DF36. The problem has happened at least twice to this particular trigger. Another trigger where the problem has occurred at least a couple of times is 000DC3E0. Neither of these trigger boxes are disabled at any point (either temporarily or permanently) during the game (ex. for civil war battles), so that can't be related.
Spoiler:
prid 9df36
WETriggerScript:
Script state = "off"
::CW_var = CW (00019E53)
::CWS_var = CW (00019E53)
::EventNum_var = 0
::EventNumClearedAfterSpawning_var = True
::myHold_var = 6
::myHoldIsContested_var = False
::myHoldLocation_var = (0001676D)
::myHoldOwner_var = 2
::off_var = True
::RoadEncounter_var = True
::TriggerOnLoad_var = True
::WEHoldImperialContestedRef_var = (0004A605)
::WEHoldImperialRef_var = (0004A603)
::WEHoldSonsContestedRef_var = (0004A606)
::WEHoldSonsRef_var = (0004A604)
::WERoadStart_var = WERoadStart (001027A6)
::WEStart_var = WEStart (0004A600)
--- Papyrus - Alias TRIGGER on Quest WERoad06 (00105D1D)
ReferenceAlias:
Script state = ""
No variables
No papyrus scripts attached
It looks like the trigger is planning to to run WERoad06 (Adventurer on the Way to Nearby Dungeon) next, but said NPC is not spawning because something is broken. I do have a game save available if that would be helpful.
Issue Data
Issue #34190: WE triggers sometimes don't rearm themselves after previous WE unloads