You have a parameterized lookup on the Assignment object. When you click the lookup on grid view it shows all values and they are not specific to that project only.
However, when going into the assignment properties and clicking the same lookup, it shows values specific to the project.
In your parameterized lookup you are passing odf_grand_parent_id.
Release : All Supported
Component : CLARITY STUDIO
This is an enhancement / working as designed. This is because there is no support for System data providers (Custom objects/ Subobjects) to show Parameterized lookup attribute values in the List view by system data providers. (For example parent_id, odf_grand_parent_id). So it will not work in the List view at this time.
*Note - there was an update done where this will work in the Team Object
See also: Lookups master KB for Clarity