@stephenw10
Yes, you are correct. That was impacting the system.
I first setup a test system in lab with same 2.6 config and performed a webgui update 2.6 to 2.7.0-DEVELOPMENT. On 2.7.0-DEVELOPMENT the system does not exhibit the issues described in first post.
On production machine I followed your instructions and applied patch "Disable pf counter data preservation to temporarily work around latency when reloading large rulesets (Redmine #12827)".
Issue appears resolved.
Thank you!