According to Greek primary radar data, reported on
Avherald, the left hand turn of 90 degrees started at 00:37. The first ACARS messages about computer failures and smoke were sent with timestamp 00:26. A sudden catastrophic event (bomb, missile etc.) is getting more unlikely.
With some experience on Hellenic Air Force Radar and some info into it we should consider some lack of syncronization between radar data and ACARS.