avrdude: verification error, first mismatch at byte

Hello guys,
I use Pro mini 8Mhz - 3.3V linked to FDTI 3.3V and I'm facing a stange issue: when I upload a sketch (with Arduino IDE), I always see this message : avrdude: verification error, first mismatch at byte 0xyyyy
And yyyy is never the same even when I upload the same sketch without any change.
Do you think the flash memory of my Pro mini could be corrupted ?

Disable upload verification in the IDE preferences and upload something and test if all seems to run fine or if you get a different error

When I uncheck upload verification, the message disappers (that seems to be normal).