Crusty failed to Learn skill upon reaching lvl24

Dear admins,
Please note that I sent my Crusty to the training center, to make him learn sewage swamp. But upon reaching lvl24 he learnt nothing. Please help me fix this.

I look forward to your reply.

[AilsaZ_949]

Hi there,

You most likely taught yourself a new skill in that slot through a skill book. Skill book skills replace future skills that monsters naturally learn through leveling.

-Ailsa