When a derived metric is used in page-by, changing values in a grid the behavior is correct. When the grid is changed to a graph, the derived metric fails to show the values in the graph and throws an error.
Object with ID "GUID" and type 4 (Metric) is not found it metadata.

Cause:
This is a known issue in Strategy Web 9.4.1
Action:
Update to Strategy Analytics Enterprise 9.4.1 Hotfix 7 to take advantage of the fix.