In the mean time, I've found that the fight-start bug can be alleviated in these ways:
1. If you have an eni in the party, make sure she doesn't have Absorption equipped among her passives.
2. If you can, run dungs with a party of 5. Bug occurs much more readily with a full group.
3. I've heard rumors (unconfirmed) that the Inhalation passive also makes it more likely to occur.