Pickit3: EEPROM erased while reading device

Hello all,
PIC16F887
I've made this test:
1)Program some EEPROM cells with fixed values, inside my program, and delete this portion of code
2)In the same program, read EEPROM cells: if values match with programmed ones, blink led
Ok, it works: even if I reprogam (preserving EEPROM), the LED blinks.
3)Read device memory

4)Led stops blinking

Any idea?
Thank you very much.