I have noticed that throughout the game, there are occasionally items that aren't lootable. This typically includes things like junk items that were never moved from where they normally sit, but just don't pop up a loot interaction no matter what you do. Occasionally, this also includes dropped loot items as well.

This problem includes all situations where you can see a loot icon highlighting the item via color quality, but can't get an interaction pop-up to loot it. One thing to consider...

Many items throughout the game are unlootable