Went and finished exploring 8.2 yesterday.
My mistake was bringing Ægon as the champ for the Superior critical resistance path. As Ægon needs crits to purify debuffs this fight was long and costly, since the only real damage was his SP2 bleeds.
In one attempt I noticed that after Bahamut got an X-Gamma charge his volatility timer disappeared and the only thing I could do was die and revive.
I powered through though and finished exploring but it cost me quite a chunk of units.
My thought is, is that a bug or a part of his program, that the volatility timer just disappears?