Trains out of nowhere bug

[eqravenprince]

In multiple dungeons my group get set up in a camp (usually in places not so populated with others). But probably once every couple hours a random train of 10-20 mobs appear out of nowhere despite us killing every pull prior. This happens even when we are the only ones in the zone. Cazic Thule is a perfect example as no one goes there. My group was hunting gators for over an hour, had cleared all gators multiple times, then all of a sudden lizards and gorillas train shows up and we are nowhere near that. There is defintely something really buggy going on. We would be at least 2-3 levels higher if it weren't for this bug.