So I had the same issue there is a workaround for this for now that I used till Bungie fixes it. When inspecting character on the bottom it shows a prompt to Toggle Vault, if you toggle you can then store stuff as intended. Hopefully this helps for now till Bungie fixes it to the way it was prior to where when you access vault then return to character, you can then store stuff this way. Till then utilize the toggle feature till a fix returns it to normal.