Yea this seriously needs to be fixed already. The other night a new player asked if anyone in the area had coarse sugar. I offered only to find out splitting didn't work anymore. To hand off the amount he needed I had to go to a vendor, sell the amount I wanted to split, put the remaining stack in my car inventory, and then buy back the smaller stack. That's nuts. It's a fundamental game mechanic, put someone on it for a few hours or a day or two and fix it.