In over 10 tries the plugin don't split the stacks right. If you have 120.000 and want to split in half its give only 1200. (values are rounded / different) And that over 10 times. Something is buggy i guess.
Best Regards
I have a potential patch for this ready, but I am holding off in case any more issues appear.
Merged post
Also, Rust has an issue with items stacking over 65,535, so splitting items in stacks above that number won't work. The next patch will have a more bearable splitting process, but isn't fixed entirely.