Quote Originally Posted by MiRai View Post
Follow ceases to function when you engage in any PvP combat
I haven't actually played the last couple of expansions but didn't they introduce a system that toggles different talent based on whether you're in PvP or PvE combat? I had assumed that /follow being disabled while in PvP combat is connected to that system. Considering that system doesn't exist in vanilla there's a chance follow may work independently.