@smitg: There is a bug in v23.8 with entitlement/entitlementtype mapping while account upload which was fixed in v23.10. Until then you may have to use alternate approach of Uploading-Accounts-and-associated-Entitlements-using-Schema-Upload

We faced the same issue in v23.8 and last it was working for us is v23.4, So in between somewhere this bug got introduced and we got confirmation that it is fixed in v23.10 and same has been validated successfully after v23.10 upgrade