I'm running a server with some engrams disabled so that players can go to a Custom NPC trader and buy them instead of crafting them.
Everything works, the engrams are hidden and the items are created at the NPC trader's table.

What I think that is happening is that, if you buy an item that has been hidden in the engrams, when you log off, it becomes unusable. When you log back in, the item is still in your inventory but you can't use it nor can you drop it or transfer to another inventory.

Has anyone noticed this "feature" or am I doing something wrong?

Thank you for your comments.