OK, I haven't experienced this first hand because I quit Onigiri before last maintenance (January 12th). My friend who still plays just told me that the new ranking system is making people DC in dungeons, and when this happens, the whole run is basically voided as if the player had never even entered the dungeon. You regain any durability lost off your weapon, but you lose any items you picked up, which would suck if you had something rare like a gem or Sui-u weapon.
Does anyone want to confirm that this is a widespread issue affecting most if not everyone? When I heard this I was like, Wow CS, you fucked up super hardcore this time.