As the title states.
A player mentioned items that were damaged/repaired (guns, jackhammers ect) were not moving between boxes. I did some testing and found the same. On my dev server, I unloaded all my plugins and still noticed the issue. As well, the items could still stack after the plugin was unloaded so, I thought to start with that. I shut down the server, removed just the Stack Modifier plugin, restarted the server, and all the items, even the damaged/repaired ones could move normally.
Not sure if this is happening for other server owners or if just me thing lol. Anyway, thought to report.