I have the same problem. When using Hueman 3.1.3, my front page was generated very quickly, and after upgrade to Hueman 3.3.9, my front page was generated from 11 to 21 seconds. To verify this slow problem, I switch back to 3.1.3, front page is back normal and very quick.
Only front page (hueman index.php) has this problem, single page is fine in Huemen 3.3.9.
Wordpress is 4.7.4
How can I debug?