Features / Usability

There are so many messages here it is hard too find what you need. I didnt find any thing about this problem.
After updating from 2.3 to 4.1 the Default sort mode:under threads dose nothing, also the option in a forum it self dosent work.
Ive tried every combination of style and search mode.
I have also tried it on a install of 3.4, same results.