Food not stacking

Was their any particular steps you took to get the fish? which furnace type did you cook it in? how did you obtain the fish? any more info to try to replicate this would be greatly appreciated! 🙂 

I cooked a few in a regular furnace, and the rest in a campfire. It might be that, but it shouldn't be splitting, right?

Food that I cook on a campfire doesn't stack with food cooked by a furnace or other means.

So far it seems to at least affect cooked fish and cooked salmon...

Same here, I have a chest that splits the raw food into 2 smokers and the food cooked into these 2 can't be stacked together