KB483550: Smart Derived Metric based on AFB Metrics end up empty

Starting with the release of Strategy ONE (March 2024), dossiers are also known as dashboards.

Symptoms

• Dossier uses Smart derived metrics defined on other derived metrics.
• The derived metric is calculated incorrectly

Glossary

• Derived Metrics
• Aggregate from Base and SubTotal From Base
• Smart Metrics  -When created a metric on web, in the metric options, set it to Manual, if both Aggregate From Base and SubTotals From Base are unchecked, the metric is a smart metric

Steps to reproduce

Since this issue only be reproduced under complex condition, we will only demonstrate the concept of Aggregate from Base (AFB) metric, and smart metric. Users who has seen the behavior changed and the related upgrade impact reference ID, can compare this example to understand the change.
This case is built upon Tutorial project. 
1. Create a New Dossier. Add External Data. Choose Clipboard and create a dataset with Attribute A, Metric B as below:

2.  Create metrics

MaxB = Max(B){~+}

MinB =  Min(B){~+}

3.  Create 

AvgMaxB = Avg(Max(B)){~+}

AvgMinB =  Avg(Min(B)){~+}

 Diff = AvgMaxB-AvgMinB

3.  When the dataset and child attributes/metric, or data relations are complex, sometime metrics like

Diff

Cause 

This is a known defect before Strategy 2019. 
This issue happens when there are many passes of metric calculation for a deeply nested metric. Sometimes in the later passes, very complex AFB metrics are not treated as calculated metrics even when they have already been calculated in the previous passes. This results in the null value in the final result. In the above example, the Engine would have one path to calculate metric MaxB and another path to calculate metric AvgMaxB using the result of MaxB. Before the fix, the Engine sometimes lost the result of MaxB, and treats it as uncalculated when generating the result of AvgMaxB.

Solution

To resolve this defect, upgrade to Strategy 2019 or above.
After the fix, smart metrics will show the correct values.
Strategy reference numbers for this technical note are KB483550 and DE111407