My group was doing T13 and one of our players crashed and disconnected. Him disconnecting caused the maximum limit break to drop to two bars, then when he returned, it reset the limit break to 3 bars, and cleared out all limit break we had accumulated. The was detrimental because we didn't even have a level 2 limit for teraflare (level 2 tank lb minimum to survive).

When you are in an instance, the limit break bar size should be fixed and not change or reset if a player drops out or has connection issues, especially if fights are designed to require level 2/level 3 limit breaks of certain kinds at specific points in the fight.