Turkish Airlines increased its Buenos Aires Ezeiza (EZE) - Sao Paulo Guarulhos (GRU) - Istanbul (IST) service from 4x/weekly to daily on 02Jul13 with a change in aircraft type from the the 777-300ER's (that it started the route with on 11Dec12) to A340-300's. Turkish will reportedly revert to 777-300ER's on 02Oct13.
In other news, reader Andreas Fliflet reports that the Turkish Airlines website allows EZE-GRU and GRU-IST bookings but not EZE-IST on select dates in January, suggesting that the airline might be getting their CRS ready to take EZE-IST non-stop bookings, which would be consistent with the carrier's recent talk of introducing 2x/daily non-stops between EZE and IST in the next couple of years.
Alternatively, the airline could be reducing frequencies out of EZE. Finally, this could all be CRS anomalies while they reset schedules but the possibility of non-stop flights is interesting.
Sources: Andreas Fliflet