Hi, I did extract of mminfo as requested to better show, but I changed the real name to preserve right of customer.
I also do not see timestamp which was requested in original query, but ok. Let's see what do we have...
I do not think this is an issue with group interval as some have proposed as then we would see other savesets following same pattern - obviously not in this case.
Next thing to do is to check logs. Run mminfo command, but this time make sure to include those (20) value so you get exact timestamps and check daemon.raw if it has anything inside around that time. Also, consider update as it has been said before. You mentioned Windows NT which bring me to question - which OS is affected client? Now, if this client is something normal and more modern, it is not a problem to have that client only updated for NW version. Which version of server do you run? Last, but not least, is this pure file system backup or you also use kind of savepnpc?