Well yes every single character has a yearly pulse and your conditions will be true for all of them, that's why vanilla only fires important golbal events on the pope and hip uses the isis character the same way. Restrict your event trigger to only fire on one of those and the major = yes flag will make it appear for everyone.
Makes no sense. I have used the same algorythm to fire other events for several characters at the same time an those work correctly. Also, the on_yearly_pulse one works fine. It's the on_character_convert_religion, on_new_holder and on_war_ended_victory cases that are doing the event bombing. Anyway I tried your solution by changing the "immediate" part
Code:
immediate = {
c_606060 = { narrative_event = { id = ri.0016 } } #Isis id = 606060
}
but it didn't work, so either I am doing it wrong or that was not the problem.
I suspect it may have to do something with the ROOT and FROM and how those on_action clauses handle them but it's just guessing. Everything I learned about modding ck2 has been basically through reverse engineering, since the wiki leaves much to be desired, so there are may be "simple" things I have yet to understand. If you could be more precise about how to fix the events I would appreciate