idle virutal CPUs show sys% usage

Recently all our systems show sys% usage, even on folded CPUs (displayed with nmon -c). For instance a system with 6 virutal CPUs, 10 of the cores show only sys usage each over 30%. This system shows 5 of the CPUs as folded.

Is this normal? It remember the folded CPUs used to show no usage at all.

which AIX version and hardware do you use ?

Software is various levels of AIX 5.3 and 6.1

Hardware is Power5 9119-595 with firmware SF240_403

Example of what is seen on our LPARs.