Long story short but my problem is what the title says. One of the robots during production time decided to roll back a file to a previous state. Some more info about the Cell integration:
It is a treatment cell for metallic pieces. 2 robots are used FANUC M710iC 50E and the cell automation is controlled by an OMRON PLC. The robots comunicate with each other and the PLC with internet protocol. 1 robot is set as master the other as a slave. In both robots there is a MAIN_PROGRAM that handles the generic automation (such as manipulator grippers and pick and place parts) and the comunication of the robots with each other and the PLC, and inside the MAIN_PROGRAM there is a call for the process .tp file which is different depending the piece to be worked. I am also using USER_FRAMES on both robots so when I need to program a new piece for grinding and polishing I do the master and then copy the program to slave. The whole cell integration and the robots are also connected to our LAN network and I use Roboguide where I have created the cell and the robots (by creating an exact copy of them from the LAN).
So 2 days ago a strange thing happened. I created a new .TP program. I tested it and after some minor changes I copied the .TP file to slave. I started the automation and after 2 hours I noticed that robot 1 (master) has rolled back the .TP file (in the state before the minor changes I described earlier). Robot 2 had the latest file. The automation never stopped and I am sure I never exported the older version of the file from ROBOGUIDE. Anyone has ANY clue as to what may have happened ???? 
