This was a stack of 500 and when I use the middle mouse to cut it in half this happens. I unloaded the custom skins stacks fix plugin and the issue stopped. 

What other plugins are you using?

I have 188 plugins so it would be hard to tell what the conflict is.  I am using AlphaLoot and I think it does something with skins now so maybe that's the conflict.  I am not sure if other players are having this issue I just wanted to let you know.

There's a few that do conflict, but most of those handle the skin issues themselves, so if you have no issues with the plugin unloaded, just don't load it. If you do figure out which plugin was arguing with it, Lemmie know and I'll add the conflict to the description.