Dehornoy's class bound for indecomposable involutive solutions

Let $(X,r)$ be an indecomposable involutive solution, and let the Dehornoy's class denote its associated class invariant. Dehornoy's class conjecture for indecomposable solutions. The Dehornoy's class is bounded by the size of $X$. The source presents this as a conjecture from the cited literature; no resolution is stated here.