Hello Justinfibe,
No, that is not normal. Was there anything else going on with the system during the observed time of high latency, like a storage failover/giveback where the FlashCache has to re-warm its contents? If nothing else was going on then I suggest you open a case with our Support Team to rule out any failing hardware, i.e. failing FlashCache, failing disks, failing shelf modules, etc...
Regards,
Team NetApp
Team NetApp