Here is the output from fstat:

uucp     usbhid-ups 63113 text /        6345098 -r-xr-xr-x  175712  r
uucp     usbhid-ups 63113   wd /         80705 drwxr-x---     512  r
uucp     usbhid-ups 63113 root /             2 drwxr-xr-x    1024  r
uucp     usbhid-ups 63113    0 /dev         10 crw-rw-rw-    null rw
uucp     usbhid-ups 63113    1 /dev         10 crw-rw-rw-    null rw
uucp     usbhid-ups 63113    2 /dev         10 crw-rw-rw-    null rw
uucp     usbhid-ups 63113    3* local dgram fffff8000db78e10 <-> fffff8000d845000
uucp     usbhid-ups 63113    4 /dev        133 crw-rw----  usb/0.2.0 rw
uucp     usbhid-ups 63113    5 /dev        133 crw-rw----  usb/0.2.0 rw
uucp     usbhid-ups 63113    6* local stream fffff8000d7f4960
uucp     usbhid-ups 63113    7* local stream fffff8000da853c0 <-> fffff8000da854b0
uucp     usbhid-ups 63113   10* local stream fffff8000db97960

Seems to be in order I believe.

Thanks for the help and lesson dennypage, much appreciated..

I'll check on it tonight and see if its appearing in the logs again as well as re-run the fstat.

Thanks again..

As for fstat, I ran it but honestly I had no idea how to interpret the lengthy list.

Sorry, I should have explained. fstat shows what processes have what files open. The output of usbhid-ups suggested that there was another process accessing the UPS via USB. So if you run

fstat | grep -i usb

while the problem is occurring, you could see processes that have USB devices open. You are looking for processes using /dev/usb/*. Here is the output from one of my systems:

USER     CMD          PID   FD MOUNT      INUM MODE         SZ|DV R/W
uucp     usbhid-ups  1214 text /        10841613 -r-xr-xr-x  175712  r
uucp     usbhid-ups  1214   wd /        8748129 drwxr-x---     512  r
uucp     usbhid-ups  1214 root /             2 drwxr-xr-x    1024  r
uucp     usbhid-ups  1214    0 /dev         10 crw-rw-rw-    null rw
uucp     usbhid-ups  1214    1 /dev         10 crw-rw-rw-    null rw
uucp     usbhid-ups  1214    2 /dev         10 crw-rw-rw-    null rw
uucp     usbhid-ups  1214    3* local dgram fffff8000b413000 <-> fffff8000b1f8960
uucp     usbhid-ups  1214    4 /dev         73 crw-rw----  usb/0.3.0 rw
uucp     usbhid-ups  1214    5 /dev         73 crw-rw----  usb/0.3.0 rw
uucp     usbhid-ups  1214    6* local stream fffff801b1ea43c0
uucp     usbhid-ups  1214    7* local stream fffff8000b3db1e0 <-> fffff8014705e690
uucp     usbhid-ups  1214   10* local stream fffff8000b1f84b0

You can see that usbhid-ups has two file descriptors (4 & 5) open on the USB bus accessing node 0.3.0.

We would expect usbhid-ups to have open files for the UPS. But if there were another process with the same USB node open, including a second usbhid-ups process, that would indicate a problem.

As for fstat, I ran it but honestly I had no idea how to interpret the lengthy list.

Squid
SquidGuard
Snort
iperf
Lightsquid
nmap
ntop
NUT
Traffic_Status_Totals

Im going to reboot and also switch the USB port to see if that helps..

Is this running in a VM?
networkupstools.org/docs/FAQ.html#_what_8217_s_this_about_emphasis_data_stale_emphasis

FWIW, Stale data in general isn't a new issue:

www.google.com/#q=site:forum.pfsense.org+nut+data+stale