If you are polymorphed in any way shape or form, DO NOT take a level until you go back to your true form. There are several possible bugs that have been associated with this.
From characters being invalidated due to an incorrect amount of skill points, which means the server will autoboot that character. To RDD stat bonuses not being applied at all, and a whole lot in between. As you can see this can really hose up your character. So please, return to your normal shape prior to clicking the level up button.
Shapechange & Shifter Bug
Shapechange & Shifter Bug

*Computers are alot like air-conditioners. They work great until you open windows*