First I would recommend to upgrade all of your FieldPoint components to the most recent version. The location of the most recent FieldPoint Explorer is:
ftp://ftp.ni.com/support/fieldpoint/Server/
Before you install the newest version of FieldPoint Explorer, you will need to uninstall your current version. Next, I would recommend that you download and install the most recent firmware for the FP-1600. You can locate the firmware at the following web address: ftp://ftp.ni.com/support/fieldpoint/Update/
Onec you have downloaded the firmware, you will need to launch FieldPoint Explorer, and browse to the FP-1600 by adding a new comm resource, or right click on the FP Res and selecting edit this device. Then click on the browse button to search for all available
FP-1600s that are on the network. Once the troubled FP-1600 is listed, double click on it to get to the FP-1600 properties. You should now see the firmware button, click on it and follow the instructions that are presented before you. Once you have done this, note the time servers IP address. This address should be a computer that has FieldPoint Explorer installed on it, with the FieldPoint time synchronization running. If it does not, then the FP-1600 does not know where to obtain the correct time from which may cause the strange timestamps to appear.