I'm re-posting this from another bug report along with my observations from looking into this one.
The GM Polymorph menu from the Add menu currently is not functioning properly. It seems to be "skipping" entries. For instance, the first three entries are Male, Female and Game Master bodies. The menu only shows up with Male and Game Master, skipping the female entry.
Moreover, when skipping, this causes issues with the entries further down the list. I noticed that if you have an even number of entries, the problem will not be noticable, even though it is still skipping every other one. However if you have an odd number, the first menu entry will show up with the menu number instead of the menu name, and so it will continue down the list.
I checked this against other Add Menu sections, and nowhere else seemed to be having this problem. I then thought perhaps this is caused by intermingling menu's and objects, but seperating Male, Female, and Game Master out to their own section did not fix the problem, it just didn't show up on the first page.
Anyhow, I looked at the Add Menu code (BuildAddMenuGump() in gumps.cpp) and could not find any obvious cause, especially given that this is a "selective" bug, only affecting (as far as I've found) the GM Polymorph menu.