Limit Break Mechanics

So, simple question here: if a group wipes on the last boss of a 4-man dungeon after filling the LB2 bar, does it reset completely, or does it only wipe away the second bar?

Ran into a player who (rudely) suggested that it would only get rid of the second bar, which caused some tension in the run (because the rest of us believed it would clear the whole thing). I'll admit I haven't paid attention, because I'm usually tanking, and I usually leave the LB alone (except for instances where I can predict a huge blow is going to be a lot bigger than expected--looking at YOU Cloud of Darkness who's eaten a few puffs), and so am not sure how the Limit Break bar interacts with wipes.

Thanks!

If I recall it only wipes away the bar that is added when you start the fight.

Aye only wipes the extra boss bar.
So don't waste it you know you're not going to make it.

Most bosses in 8-24 man content wipe the bar to zero at the stars.

Typically Garlemauld Bosses like Nero, Regula, and Gaius wipe the bar to Zero no matter what it was at the start.