Thanks for your response.
I tried the above solution and it worked fine for 10 vusers for 10 min. When I try to run my regular load test (this time reduced number of Vusers to 50%), I still see the same issue.
would be good to know if your MIlistener is a dedicated machine or a Virtual one - is on VMWare
We are not using controller as load generator. We opened ticket with HP on this and hopefully this will be resolved soon.
Thanks