Yes, the miles were transferred from my C1 account.
Family members were added to my account right after I created the account, so that's is not the reason.

I found this thread. Many people have the same issue. The workaround is to book by phone. But my flight is not visible to phone agents for some reasons.
https://www.flyertalk.com/forum/turkish-airlines-miles-smiles/1951305-award-ticket-only-membership-owner-3.html