Originally posted by FTZ35:

One possibility that i can think of is that recently I have restored an older save and that might have messed up the event triggers....

I'll say no to this. i don't play with mods or have ever restored an older save. Maybe having a main base in the Plains does prevent other events from triggering, leaving the "You are being hunted..." as your sole event since, as Ammikaameri pointed out ""You are being hunted..." event which doesn't require player base" .