Well, I spent about 3 hours on the Turkish side a few days ago. I crossed at Ledras St.

The Turkish side scanned my passport on entry and exit.

Exiting the Greek side, the officer only looked briefly at my photo. Re-entering the Greek side, was waved through without showing my passport at all. Maybe he remembered my face, as I'm of an ethnicity that isn't very common on the island - I saw one other person of my race the entire 3 days I was there (not that I was looking)

However, if the Greek side doesn't scan or even look through the visa pages of your passport then there is no way they would know you entered from the North. It may be different if you are not an EU/EEA citizen.