I found a fishing trap in a random trash pile. When I clicked on it in my inventory, the console immediately spammed a divide by zero error message repeatedly for around a minute without stopping. I noticed that the icon for the fishing trap did not show a number. I clicked on a different item in the inventory which was selected and displayed correctly, then clicked on the fishing trap again and it resulted in the same divide by zero error message loop. I exited out of 7 Days back to the desktop and then restarted it, reloaded the game world, and tried again to receive the same error loop when I selected the fishing trap. At that point I checked in the xml files to try to assess what may be causing it. I noticed that there was both an economic value of 0 and an economic bundle size of 0 for the fishing trap, which from what I recall was the only item in item.xml with both of those settings set to 0. I figured that it was probably trying to assess the value of the stack (of 1 fishing trap) when I selected it and so it was likely trying to use either of those values in its calculations. I tested setting the economic bundle size to 1 first, saved, restarted 7 Days, reloaded the game world, and was then able to select the fishing trap without being spammed with the divide by zero error messages.
Since the value of the fishing trap is set to 0, which means that it technically has no sell price, it shouldn't make any significant changes trader-wise to set the economic bundle size to 1; it's not like it's the same as the stack value.