Top report bad cpu states

Hi,

When I run heavy network load on my machine top is reporting bad cpu states - for example 100% idle although the cpu is working very hard, sometimes is reporting states with high jumps - for 1 sample it's 20% idle and 1 sample after it's 80% and these jumps repeat themselves.

It happened on both RHEL7.4 and 7.6.
In RHEL8 it's working perfect on the same appliance with the same tests!

Can someone refer me to a fix or a patch I can apply on the kernel in order to fix that problem?

Thanks!