Klocwork 10.0 doesn't understand grouping:off option in query which plugin sets by default.
For it to work with KW version <10.4 plugin shouldn't set the grouping option.
We're now migrating to newer version of klocwork so that won't be a problem for us in the future, but for many folks that are sitting on KW<10.4 it might be a problem when trying to use new klocworkQualityGateway in pipelines.
For freestyle projects you should be able to use deprecated klocwork Gateway.
I know this issue is old but I'm leaving this for anyone who stumbles across this problem.