AbstractInvocationHandler logs ERROR even if invocation fails with SOAPFault, which is IMHO wrong.
It is to be handled like @ApplicationException, the service implementation too care to raise a SOAPFault.

catch (Throwable t) {
WSLogger.ROOT_LOGGER.methodInvocationFailed(t, t.getLocalizedMessage());
handleInvocationException(t);

The current implementation leads to excessive false ERROR logs, which is unpleasant in production environments.