Problem with EDS P3 of ABB

We are having EDS P3, running on DEC Alphastation 400 with Unix 4.0 OS as our engineering station for ABB Procontrol P13 system. The processors of Procontrol P 13 (70PR05b) are recently re loaded using the engineering station (EDS P3). After the loading, the status had indicated no difference between the programs in the processor and the EDS. But after a few days, it started showing difference between the programs (indicated in terms of time). Our effort to reload the program from EDS failed, till we logged off from the session and logged in again. We loaded the back up Application program in to EDS, compiled and reloaded the program. Then the EDS has shown no difference between the program in the 70PR05 and EDS. Today, when we checked the EDS, it is again showing that there is difference between the program in EDS and the processor. The system, which is controlling the Gas Turbines is running (indicating that the program in the processor is good). Can any one help by giving the reason for the above problem and the possible solution?