Since iOS 7 when you type using Greek language on keyboard either typing a mail or a tweet, a Facebook status update, an SMS or a Page document you got this bug.
The bug is very easy to reproduce.
Open a new message and type a greek word that ends to letter s (ς)
For example δυνατός
Example
Now while the cursor is after the last letter ς| hit backspace to delete just the last letter. (don’t press space after you type the word)
It should only delete the letter ς but instead the whole word is deleted.
It’s been reported numerous times through apple beta testers and users.
Every Greek iOS user since version 7 got this issue. On iPhone or iPad, with Bluetooth keyboard or touch keyboard its still there. So if you're writing in Greek language and having the same problem maybe we should let Apple know about this.
Το στελνουμε ολοι μαζι οπως εχει το κειμενο;