Hi
first of all. initiate "SP reboot" on the nodes ASAP., the operation by design is not user disruptive - however. it might i believe that theoretical that itself might trigger the bug.
After doing that, you can decide if you want to upgrade the SP or wait another 500 day (preferably run the next "sp reboot" around the 400 days).
if you have FAS32XX/FAS62XX/FAS22XX and you running non fixed BIOS version (see below) , that upgrade or reboot can trigger another bug https://mysupport.netapp.com/NOW/cgi-bin/bol?Type=Detail&Display=702464
there is a workarround in the bug to fix it if crossed. the fix for this issue is in the fowwoling BIOS versions (taken from the buios version download pages) :
BIOS 7.3 for FAS62XX
BIOS 8.3 for FAS22XX
BIOS 5.3 for FAS32XX
Gidi