Kristoff never loses the sprint in Vlaanderen or Roubaix, it's just rarely for 1st.I either lost in your post or I don't understand. The only year when Kristoff won Tour of Flanders was in 2015, that was when he was in leading duo with Terpstra and GvA and Sagan duo was chasing them.
Maybe you mean Kristoff's MSR win?
2020, wins sprint for 3rd
2019, wins sprint for 3rd
2018, 16th, loses small group sprint to Demare
2017, wins sprint for 5th
2016, wins sprint for 4th
2015, wins 2 man sprint for the win
2014, finishes 5th solo
2013, wins sprint for 4th
Roubaix he won the group sprint for 9th/ 10th both times he didn't finish 15 minutes down or DNF.