My experience: Seagull steals entire lunchbox from "Spice of Life: Potato Edition"
The issue is simply that a seagull will have the ability to steal a lunchbox, which is a container item that can hold many stacks of #food.
I encourage anyone to comment with additional information, as I'm only going to provide a description. I've turned off stealing items, but I'd prefer a blacklist to be implemented, if possible.

I am having a similar issues except that even when stealing is turned off they continue to steal.

What is the formatting for this? I tried putting solsweetpotato:lunchbox in the brackets for the blacklist but it failed to read the config and crashed. And what's the formatting for multiple items?

I honestly wish there was a "default" preset for this as having this happen repeatedly is very annoying. At best it should just not consume the entire container and drop the empty one instead.