Some questions:
Are you using an IPS policy besides NULL?
Is prevention enabled in the IPS policy?
Do you see any Warning events in red in the DCS console?
Have your tried enabling Trivial Logging?
One way to make sure that it is not DCS policy is to apply the NULL policy and see if the block still happens..
To be sure, you can uninstall the agent and reboot and see if the issue still occurs.