Exactly 24 hours. The DDOY VI sends out the current time in our custom format. Fortunately it's made it easy to manually fix.
YYY = Year
DDD = Day Of Year
HH = Hour
MM = Minute
SS.S = Seconds to a fraction of a second
Some NIST servers are configured to lock you out when you query too quickly from the same IP address. Try using a different server. If you still get the same behavior, try querying the server by two VIs on your host computer (making sure that the two VIs query close to the same time). If you get the same behavior, then the issue is with the server.
The most my VIs sync with NIST is twice every two days and the move one can request a time sync is once every four seconds.
My alterations seemed to have worked though. New files were created and the time values have been consistent so far. If irregularities crop up again I'll add an update.
Thanks for the update. If you would please, tag the post where you described your alterations as the solution to this post so other readers may see what you did to fix the issue. If you have any further issues, please post back. Thanks!