As far as I can tell, items have to be ‘properly’ stored in order to be available for sale - that is, in Stockpiles or Storage Chests of some flavor. From those pictures, it looks like your items are just scattered on the ground, so they’re not “supposed” to be available for sale.
Thus I’d guess this is more a symptom of the current problems with getting items to store into stockpiles/chests successfully.