I was battling Taen in Perfection Base (right before you get your Mega Stone) in 1.1.7 and my Delta-Charizard fainted from Life Orb the turn I KO’d his last pokemon. (I had an un-hatched egg as the last slot of my party, as well as one empty slot). The game acted like I won the game, however it also displayed my entire party as fainted.
This meant that the next time I entered battle, the game crashed as it could not find a pokemon to send out. I ended up getting out of the situation by using repels until I made my way back to the Pokemon Center, which fully healed my team with no issues.