Irreducibility conjecture for generalized vector bundles on ribbons

Let $X$ be a ribbon, let $r$ be a positive integer, and let $\delta=-\deg({\mathscr N})$, where ${\mathscr N}$ is the conormal sheaf of $X_{\mathrm{red}}$ in $X$. Fix the generalized degree and an index $b<r\delta$ of generalized vector bundles of generalized rank $2r$. The irreducibility conjecture. The locus of semistable generalized vector bundles of generalized rank $2r$ and fixed index $b$ on $X$ is irreducible in the moduli space. If true, its closure gives an irreducible component of the Simpson moduli space. The conjecture is known for quasi locally free sheaves, generalized line bundles, and certain split ribbons, but remains unproved in the stated generality.