So while playing around alot with modded events and getting problems here and there, I tried to see the behavior of triggered events.

There are actually 3 bugs with the event system or at least I do not see them as working as intended.

First Bug: 

A very simple event I made is this: 

On Turn begin, get 5000 fame. Starting in Era 0, no prerequisites at all on Empire_Self, event gets consumed after trigger.

One would believe since every empire meets the prerequisites, the effect should apply to every empire at same time, right? It does not. Each Turn, starting with you on the very first turn since you are Empire 1 (or 0 in index terms), the next empire gets its reward. Meaning. Empire 4 gets the fame on Turn 4, Empire 8 will get the fame on Turn 8 and so on.

Mod_FirstBug.zip

Mod_FirstBug.unitypackage

Second Bug:

You can set the option for an event as "Prevent Event Removal". The Tooltip says, it allows the same event to fire several times in a playthrough. The problem is, if this event is defined for several eras, it will only Trigger in the Era several times it first triggered in.

Example: The event should trigger in Era 2 and Era 3. If it ever triggered even only once in Era 2 it will never trigger in Era 3 even if the event meets its prerequisites there.

This issue only works with a new game, because loading a savegame will let you see issue 3 with the event.

Mod_SecondBug.zip

Mod_SecondBug.unitypackage

Third Bug (tied to the second bug):

After loading a savegame, the second bug will behave differently. If you do 10 turns on a new game you will have 50k fame (and not changed era). If you load up any previous turn save (for instance Turn 5), the event will trigger instead for the next empire all the way until a) it does not meet the prerequisites anymore or b) changed era or c) you load a savegame again. Can even be a save you made this turn, does not matter. The event won't trigger for that empire which triggered before the load but for the next empire. Which means the trigger after loading gets carried to the next empire index and only he will trigger the event and will do so until a), b) or c) happens.

This will happen until you have loaded the game n times, where n is the number of empires in the game. Afterwards it will just not trigger for anyone.

This is also true if the event had a prerequisite which limits the benefactor of that event. For example: The sample event only applies to the empire with the Phoenician Culture (it uses the legacytrait as pre-req). It will trigger each turn in Era 1 if you chose that culture. If you change to era 3 OR load a save from a previous turn of Era 1 the event will not trigger ever again.

Mod_ThirdBug_Phoenician.zip

Mod_ThirdBug_Phoenician.unitypackage

The second and third issue cannot be reproduced by a savegame and need a new game otherwise you cannot see the behavior. But I attached the Mod (extract them into you Community folder) and the unity modpackage for them.

The first bug is easy enough to see when you just start a new game with any number of empires and the mod.