Example: I have Jabber account in Miranda and ICQ account. I have metacontact with 2 subcontacts: one is ICQ contact and the other is Jabber contact. See the attached picture. Thus, I see from which MY account the info was taken in the first case and in the second case.
If I delete one of these subcontacts, I will have exactly what is shown in your screenshot. This is the answer - probably you have a metacontact with only one subcontact.
So you can solve your problem by 2 ways:
1) Edit the metacontact by removing this single subcontact from it. Meta will be disbanded and sub will turn into regular contact
or
2) Disable metacontacts support in Miranda completely.