When perusing a merchant's goods, it is possible to select a particular category of items (armor, weapons, consumables, or "other"); when doing so, all items that don't belong to that category - either in your inventory or in the merchant's store - take on a semi-transparent effect meant to "grey them out."
However, that semi-transparent effect does not go away when you close the merchant interface, and in fact persists in your inventory.
SAVED GAME: link
(yes, it's the same as the saved game in my clipping bug report)
REPRO STEPS:
Load the attached saved game.
Talk to Dengler and ask him to see what he has.
Go to the trading interface, and select the "other" category (the one whose icon is an ellipsis).
Observe how all items that don't pertain to that category are "greyed out" by means of a semi-transparent effect.
Exit the trading interface and go to your inventory.
Observe that all items you have that don't pertain to the "other" category are still semi-transparent.