@jackie_w: I suppose the brute-force approach of replacing
/bin/dosfsck with an
up to date build (careful: not the same filename, fix it) would at least fix it on reboot until the next FW update.
(Fair warning: if I screwed up, this will break the boot horribly. Hopefully leading to an instant factory reset on boot. Emphasis on *hopefully* ^^. I did try a dry-run manually with no ill effects, and the commandline arguments haven't changed, so, it *should* behave. But, here be angry potentially disk-eating dragons).
I'm vaguely hoping Nickel itself runs a fsck before remounting onboard after an USBMS session (which would fix it *always*), but that may be wishful thinking

.
EDIT: The udev script run on unplug would seem to concur with that theory, yay.
----
And, yeah, only ever happens on the Forma on my end, too.