Minor inconsistencies with scanning

Tarkannen

I was playing the other day and exploring a wreck which had a Floodlight, Chair 3 and one of the plant pots inside that I hadn't scanned yet. Further in past a Sealed Door, I was delighted to find an extra Exosuit fragment and three Propulsion Cannon Arm fragments. One thing I noticed when scanning them, is the fragments disappear but the miscellaneous items remain behind. I know the 'tech' items vanish to keep from unlocking stuff from one fragment and repeats will give Titanium, but why don't the other scannable items vanish as well after they've been scanned? I know it's not a bug, but it seems weird that you would leave behind raw materials to be used, especially since most miscellaneous items need Titanium to be crafted.