Myers's conjecture on a three-color Rado number

Let $R_3(\mathcal{E})$ denote the smallest $n$ such that every 3-coloring of $[n]$ induces a monochromatic solution to the equation $\mathcal{E}$. For $m\ge 3$, consider the equation $x-y=(m-2)z$. Myers's conjecture.

$$R_3(x-y=(m-2)z)=m^3-m^2-m-1.$$

This conjecture gives exact values for a family of generalized Schur-related Rado numbers. The source does not state whether it has been resolved.