Message "Intentional Tampering may have occured"

Hello

I have a “Domino 6.5.4 Fix2 LangPack Italian” environment and in these days I find that sometime, when I open a database, I get this message on Lotus Notes Client (in the down-bar):

“This document has been altered since the time it was signed! Intentional tampering may have occured”

The message occurs when try to open my personal mail database with the Administrator ID but some user (2) have find it when open their mail db.

This message doesn’t give problem but I would know more information about it to prevent possible question of my user.

Anyone have see a similar message?

Thanks you very much for support,

Regards,

Luca Chiozzi