So what may be happening here is that both data source microflows for your dataviews may be running at the same time (page load). That would result in an empty object being passed to the nested data source, hence no data being shown.
Then once an id is added and the Get Account button is pressed, you’ll see the id in that instance of ACT_ListAccount but that isn’t populating the nested dataview because it was called from the button, not the dataview’s datasource (that’s assuming the ACT_ListAccount microflow is called from that Get Account button).
Maybe try adding visibility control to the nested dataview so that it only becomes visible once the id field is filled in. This would ensure that the nested DS only runs once the containing AccountList object has an id. This may require some adjustment of the Get Account button logic (or maybe an on change microflow) to make sure the visibility is enabled at the right time.
Hope this helps!
Are you sure you are logging the attributes from the object you are returning to the 2nd data view? Because returned object might be empty and that would explain seeing empty fields.
Also does Get Account button have synchronize/save changes or a microflow/nanoflow behind it?