Oh wow, I don't know how I missed that. Thank you! Perhaps this should be patched so that you at least get notification of receiving the item and it being sent to the postmaster, all it showed was weapon parts and glimmer. Thanks again.

The Icons which appear on the side of the screen are the items you are directly receiving in your inventory. This is to show you what should be there when you open up your character menu. Items that go to the postmaster don't so you the icon, so that you don't go searching for it. - That said, I do think they should add a different/separate side screen icon for items that go to the post master. You should post in the #feedback forums, as a suggestion for the game.