Unable to assign an unassigend asset line

I have created a Capital project and have assigned 3 assets to 3 top tasks.

I have entered costs at the lowest level task under a top task which does not have an asset assigned. The Capitalisable tick box is checked.

In the Capital Project Form, the Costs (5000 EUR) as visibile in Column CIP.

I expect to find these costs when I open the Lines SubForm and Query on Assigned = No.

However this is not the case. How can I either expense these costs or assign the costs to one of the 3 assets under this project and then transfer to FA?

Regards