RHEV-H : Only half of CPU's available after hypervisor upgrade to v3.0.5

Hello...me again.

I've just upgraded a hypervisor from v3.0.3 (20120320) to v3.0.5 (20120510) and have noticed that the available CPU's being reported by RHEV-M has been halved. Prior to upgrade I had 24 CPU's , now its showing just 12 CPU's.

The hardware itself is fine with both CPU's healthy and operation and with hyperthreading enabled.

The issue was highlighted when a VM with 16 vCPU's was unable to live migrate to the upgraded hypervisosor. RHEV-M complains that not enough CPU resource is available on the target hypervisor :-

Cannot migrate VM. There are no available running Hosts with enough cores in VM's cluster .

Anyone else seen this ?

Case :- 683080