It's really easy to accidentally add a bunch of empty firefly jars into your SDB full of full firefly jars, and a huge pain to fix it, unless I've overlooked something. I haven't tried, but would assume there is a similar issue with potions that are full vs. half-used.
I just thought I'd mention it here. It's not really a bug, but the feature could use a little tweaking. That being said, I really love the SDBs! They're excellent!