Yes, I have several types of items with a 999 stack plus another stack. So, sometimes the rollover seems to work. Maybe it works if I'm at 999 in a stack and a new stack gets created with the drop, but it fails if I'm at <999 in a stack and the drop puts me over 999. That is, maybe the failure occurs due to having to "write" to two different stacks?
Thanks for the inventory check and fix. In my recollection, I actually have never experienced the selling problem, but I appreciate your help.
Edit: Originally, I was thinking the error occurred when a new stack needed to be created, but the number of stacks was already at its limit. However, I have 51 stacks and slauki had 40 stacks, so something else seems to be at work.