You know what’s especially odd? The fact that it crashes when the utility belt containing the reinforced knife is activated. Not when the knife itself is drawn. You don’t even get the menu. That means the game isn’t even trying to draw the item health bars at the moment it crashes.
Here’s something else funny: I went looking through the jsons and it looked like the utility belt was the only item that both had tool uses and functioned as a sheath. Well, since the utility belt is also the only item causing this problem, that seemed noteworthy.
So I went into tools.json and slapped SHEATH_KNIFE into the USE_ACTION line for the toolbox. Fired up a new game, left item health bars on, made a reinforced knife, used the toolbox, and could sheath and unsheath it from the box without issue.
Then I went and replaced the entire USE_ACTION line for the toolbox with the one from the utility belt. Fired up a new game, spawned a toolbox, and sure enough had a toolbox with all the same functions as the utility belt. Except I could still sheath and unsheath reinforced knives from it, with item health bars on, without issue.
I don’t know if any of this is helpful or not but there it is.