Key not spawning?

[Raidou Kuzunoha XIV]

I know this is a long shot since this game doesn't seem very popular and likely hasn't really got any active discussion going on any more, but I was wondering if anyone else had this game breaking glitch in chapter 22 (volcano interior/hell's gate) where a chest with a key that spawns in the room with the platforms simply doesn't spawn? I can't find anything about this (though there's no shortage of other known game breaking bugs), and I've tried everything I can think of to try and get it to spawn (restart the game, the PS3, killing myself in-game, etc.), but nothing seems to work. Anyone have any advice?

 

My last save is back from chapter 19 in my cloud storage, which isn't terrible but this game has been mediocre at best and I really don't want to have to replay any large section of it if I can help it. The only reason I decided to play it was because it was a PS Plus game from a while back that's just been sitting in my PS3 backlog for a while, and I thought I'd give it a go.

 

It's insanely disappointing with how close to the end of the game I was, and how close to the platinum I was, but if there's no way to fix this glitch, then I think I'm done with it.

[jcvd_fan]

I experienced something similar at the end of the game, but it sorted out itself... I had to do many runs at the Volcano Interior on Nightmare difficulty and in one case in the Lava Islands room the chest completely disappeared after beating the rats and falling into the lava... It appeared again only on the next run which was loaded from the last save game. In another case (again, only in one single case out of many runs) the chest in the Field of Lava room did not spawn the key, but funnily enough the gate did not have the lock on either and it just opened as a regular door without the key.