Well it's actually opposite. LDAP doesn't support PEAP MSCHAPv2.
What identity store are you referring to? Can you please go to Access-policies > default network access > identity. Let me know what you see there. If you have a identity sequence store selected there then go to User & identity store > Identity store sequence and edit the one you have selected for wireless authentication. I will be able to tell you why you're seeing this error.