I've seen a huge drop in my analytics for threads in two specific forums since I upgraded to XF 2.2. CTR is the reason for that drop not the SEPR positions, which still the same. People won't click on 15 years old thread, even if we keep content (articles) always updated in those threads.
I had publish dates removed for those threads in XF 2.1.x but I can't find a way to do that in XF 2.2.