Adalon's illusion and improved shapeshifting?

[Cognoscentus]

After receiving Adalon's illusion spell with Cernd shapechanged, the game crashes. Having him shapechange after the spell is cast also crashes the game. The error message reads "an assertion failed in chvidimage.cpp at line number 899". I have never used Cernd before, so I have no idea if this was an issue in vanilla BG2.