Just had it happen again. some raiders dropped weapons.
i unforbid them and expected them to be hauled to my main dump which has every weapon and apparel selected among other things. 0-100% durability and any quality.
the guns lay there for a few days, i attempted to manually order a haul but got told
'no open locations'. save the game, reload the game and everything is back to normal.
so... nothing to upload since the save doesn't preserve the bug. The colony is two years old. dunno what else to say.