Grub OS-probe misses Prox-Mox installation

As the title indicates with the most recent updates grub OS-probe script misses a ProxMox installation in a different HDD .

Calling the update-grub script finds correctly several others instalations such as MX Linux, Manjaro, Windows , Artix , Archbang but not ProxMox.

Although ProxMox is a Debian based Distro installed in FAT32…
Any ideas why the update-grub script is missing this one ?