Mid has been Katarina's lowest winrate role for like all season other than the first month.
https://www.leagueofgraphs.com/champions/stats/katarina/all
Currently her 4th most favorable role and her lowest popularity rate mid lane so far(88% and still dropping), Katarina has spent nearly the entire season with Mid being her least successful role.
I really didn't know how to feel about this at first, it's not uncommon for low popularity picks to have inflated winrate, but what concerns me most is that Katarina Mid winrate is just -always- the lowest, or 4th lowest winrate role for her this season.
For example, Zed has similar popularity rates to Katarina, and he even wins top 52% currently, higher than his midlane winrate. But Mid is just never straight out his lowest winrate like how Katarina's is.