We can check out the Data Quality - Summary report, right-click the Total Unallocated by Modeled Metric (Cost) table border > Copy to clipboard. Then we can paste the copied table to any other report if needed.
After we paste the table, consider also:
Right-click table header row > Show/hide columns > Unit: Check box.
Now we see all rows from all objects in one table.
Filter the table by % Unallocated > 0 to show just the fallout.
Each model metric also comes with its own fallout table showing the same information as the example above.
For example:
(left) Project explorer > Metrics > Cost.
(top center menu) > Unallocated.
