It looks like it may be a custom activity previously created and renamed, or copied from somewhere, or perhaps a 3rd part CIQ app. Connect the watch with the USB cable to a computer, and look at the folder //GARMIN/Sports/, looking for unwanted activities in Greek. Delete those files. If it does not help, do the Master Reste of your watch to factory defaults with deleting all data. Should it happen that the unwanted activities are still present on your watch even after the reset, contact the Support.
