I'm not sure why event 12, 13, 15 and 16 all have the same condition..
If it's true in event 12, it has to be true in its subevents..
Also I would make event 18 a top level event..
Event 18 is already a triggered event, so the trigger once subevent is not needed..
Using trigger once as a subevent could be an issue, why not put it as a condition in the event itself..
(you seem very fond of unneeded subevents)
I don't see any reason why it wouldn't work than, but I don't know if any of the events not in the screenshot are conflicting..
It seems there are more subevents of the story=0 below..