On bts 1.0 I had account banx.io if I try and add the private keys it fails saying that the name of the account is incorrect. It is not listed [when i call list_accounts banw 10] which should be in its range and if I try to register it as a new account it fails with is_valid_name( name ):.
I have to assume that the name is no longer valid on 2.0 which should not happen. So this must be a bug in the name validation routine.