Boileau–Boyer–Cebanu–Walsh rigid cusp conjecture

Let $\mathbb{S}^3\setminus K$ be a hyperbolic knot complement. A rigid cusp is a cusp whose Euclidean $2$-orbifold cross-section is one of $S^2(2,3,6)$, $S^2(3,3,3)$, or $S^2(2,4,4)$.

Rigid Cusp Conjecture. If a hyperbolic knot complement $\mathbb{S}^3\setminus K$ covers an orbifold with a rigid cusp, then $\mathbb{S}^3\setminus K$ covers an orbifold with an $S^2(2,3,6)$ cusp.

The conjecture predicts that every hyperbolic knot complement covering an orbifold with any rigid cusp type also covers one with an $S^2(2,3,6)$ cusp. The source's results provide evidence for it, and the source does not state that it has been resolved.