One other thing to note is that the CPU is spiking on this SVA and the other is not.
SCM: Aggregated ScanPolicy is NULL!! log line is related to MOVE Agentless 3.0.0 new feature called "VM - Based Scan Configuration" (or Policy per virtual machine).
This feature is fully dependant on "Data Center Connector for vSphere 3.0.0".
One of the potential reason behind this log line can come could be that either connector extension is not checked in into ePO or if it is checked in, then it has not yet discovered the vCenter hierarchy into ePO.
Other reason could be that McAfee Agent is not able to pull down appropriate policies to SVA mcahine.
Also, this feature can be enable/disabled on specific SVAs by unchecking "VM-based scan configuration:" displayed under "Scan Settings" tab in SVA policy, see following image (a screen shot of SVA category policy where we have kept the feature disabled and finally applied this policy on SVA or group, where we want to keep the feature as disabled):
So make sure that before enabling "VM-based scan configuration:" you have checked in "Data Center Connector for vSphere 3.0.0" and the vCenter hierachy is visible in ePO and also agent is able to pull new policies back to SVA machine.
Please do let us know how your policies etc are configured and how the environment is we can troubleshoot more on this.
Thanks & Regards,