Can you try opening it up in 0.54? Something may have changed since the last release to make it work again. If not, then the best thing to do is to zip the autosave and load it onto the issue page (#487) for our "experts" to have a look at No guarantees though...
My items kept disappearing in Gloomy Cave VII. Unknown spells came from nowhere. Some god must be playing tricks on me!
Dunno if the gods have anything to do with it. It's more likely to be the frogs. Or at least one of them in particular...
Probably you need to get close to it real quick and give it a couple decent blasts with a wand.