Quote Originally Posted by 3c-33 View Post
1. completely random busters, honestly no way of knowing when they'll do it. In particular for this kind I can only think of dohn mheg's second boss (unless I'm dumb but I swear I can never tell when it's going to come out so I end up getting chunked for 3/4 of my hp every time lol) and I'm sure there's others I can't remember right now
That boss's TB isn't as random as you think. It's called Rake and it follows the rules of your second example. The first one happens a few seconds after you engage him. So if you lob to pull, then run through him while hitting your next GCD, by the time he spins around to face you and not the rest of the party, he's about ready to nail you. He does another one after a specific set of mechanics but I can't remember which off the top of my head.