I know cooking items can be an issue as well.

For example if you are making queens jam and have two stacks of raspberries.. if you finish off one stack it can make the other vanish.

Were the fish all in one stack?

I have got to the point of making sure I have only one stack of materials for an item I am cooking.

Fish are a bit of an annoyance to get so I really hope this gets figured out and fixed at some point.