Pretty common in Western Anatolia considering even the isolated Yörük villages got the Balkan migration following the Russo-Turkish War. I can even say that an average Western Anatolian may have a 50-50% chance to have such an ancestor in the past. But this is something deeper, and already absorbed in most cases.
Having a recent Balkan ancestor is also common but only in some cities: Eastern Thrace as a whole, Bursa, İzmir, İstanbul, Eskişehir, Kocaeli, Çanakkale, Balıkesir, Manisa, Bilecik, Aydın, Yalova, Sakarya, Kütahya, Ankara the ones I recall immediately. In addition, there are Balkan communities who live together and marry only among each other.
https://i.ibb.co/qDhT4SL/9ef7ef99-51...03d68f8956.png