No statistics available (virtuals, cpu)

BIGIP 11.5.1 HF6

Noticed today that statistics for all virtuals are showing "0" even though traffic is actively passing. Data traffic seems unaffected, so far it appears to only be an issue with statistics collection and reporting on the device itself. I do not know how long this has occurred; no changes to the system for some time. It could be something that occurred 'long' ago and was just noticed.

Other possibly related information:

-Comparison of 'show sys services' indicates that the only daemon not running on active that is running on cluster standby is the racoon daemon. I do not believe this to be directly related to the stats issue since that daemon appears to be related to IKE exchange. Could be another symptom of an underlying cause if memory leak.

-'show sys cpu' only displays the first line of utilization. The remaining output that normally shows individual CPU stats only displays a single line "Host:" with no other info/stats.

Likely a brute-force fail-over and reboot would solve this, but I'd like to identify the culprit for future reference as well as try to understand why it failed in case there is a larger issue lurking that needs to be addressed. Appreciate your time and feedback.