i wouldn’t call it a bug, maybe an exploit, but it’s funny nonetheless :).
Meat sandwiches can be disassembled into bread and cooked meat, regardless of what ingredients were used to make it. I have made it with bolognas, for example. Now i can use that recipe to craft aspic, which is non perishable - a good way to store those bolognas indefinitely :).
Definitely what I’d call an exploit hahaha. Not the worst one though, not by far.
You shouldn’t probably even be able to disassemble sandwiches, I mean, the bread would get moisty thanks to the meat…
Sandwiches can also be made with hard tack.
Moisty is my new favorite word.
yeah, not gamebreaking for sure 
This actually forms a different Question: Why >can’t< you make Aspic from Bologna, or basically from most sausages or meat products? There is Fish-Aspic out there, and even Curry-Aspic (Thailand, of course :P), Why not a Sausage/Bologna Aspic?