Ayyer–Mallick's maximal-degeneracy conjecture for asymmetric annihilation matrices

Let $M_L$ be the Markov matrix of the asymmetric annihilation process on a system of size $L$. The characteristic polynomial has only $2L$ distinct eigenvalues out of a possible $2^L$. Ayyer–Mallick's maximal-degeneracy conjecture. The matrix $M_L$ is maximally degenerate in the sense that it has exactly $2L$ eigenvectors. This conjecture is posed as the question of diagonalizability of the Markov matrix after the characteristic polynomial has been determined; the supplied text does not state whether it has been resolved.