When you log in, you're allowed to see any and all customer information, because you're not limited to any specific view.
Iris uses views to filter customer access. If the customer user is assigned to any specific view, when they log in, they will only ever be able to see data belonging to a view beneath their own. That may be child views as well, but if you think about the view structure as a tree structure, they will only be able to view down the tree, and not above the view applied to their user.
If links are added to the map and you're able to view them correctly, then the data for the link is correct. However, if the customer logs in and sees grey link, then it means the customer is not allowed to see the data for that link.
The only way to allow the customer to view this data would be to make sure that the link (mnemonic) belongs to a view beneath the customer's access (view).
Find the relevant mnemonic using the filters and click on the mnemonic to edit it.
The mnemonics pop-up will be displayed. Assign the correct view to the mnemonic and your customer will now be able to see the same data as you. Click Save.