Confusing Restricted Names

[Iscah]

I made Moses one time and when I tried to name him Moses it wouldn't let me so I had to name him Oldtestament Prophet.

I would be very surprised if "Moses" was the problem, unless there's some extra meaning to the name that I'm not aware of either.

Did you try it with any other surname options? More likely it was spelling something obscure between the end of the forename and the start of the surname.