So I just started a new game with an existing character on the original Diablo. In the old days with the disc version, if you loaded a new game with an existing character or started a new game, all the inventory stayed with the character.

I started a new game and my excellent sword was missing. Just gone. Re-loaded and this time an extra leather armor I had in the inventory was gone. Can't get them back. Anyone heard of this?

I wonder if this is a new bug...

As i understand it, the GoG version of diablo isn't the same as the original. Rather debugging data was used to reconstruct the source code manually to get as close to the original as possible.

Thus, this may be a new bug.

I dunno if it'd help but GOG does have a Diablo forum - gog.com/forum -> search bottom left