It's not exactly a bug, but more of a punishing game design thing.
Dropped items in the swamp get immediately swallowed by swamp holes. That's cool enough if there's a recourse to get them back through some sort of search...maybe through application of "swamp lore" skill.
As it is now, you can just lose custom weapons incredibly easily. I'd be perfectly happy to spend an hour looking, I just feel like I should be more likely to find something if I do spend the time or have the skills.
RIP my dagger, thanks leap attack.