He believes his left flank is unbreakable, so now he's trying to shore up his right.
Except that's not how it works. The left flank won't just sit idly while their candidate appeals to their right, usually when this happens it caused reformers to hemorrhage their left. Without a clear party line on rightist deviations it'll just make voters lose faith.
And then when they lose, the left will be the ones to blame: not the rat fucking happening in the elections, not the candidate making bonehead moves, but the voters somehow.