Dynamic Calc Question

Summary:

I have a dynamic parent with two children. Child A (+), Child B (+). When running a calculation script, Child A rolls up to the parent, while Child B is #MISSING.

Why does one child roll up to the parent and the other does not?

Content (required):

The chart below demonstrates what I am seeing when I pull the data via SmartView.

When the calc script initially runs, all blocks are cleared using @idescendants("Parent").

Then, when the script completes, Child A roles up as expected, but Child B.

There is no aggregation that runs, but SET AGGMISSG is on.

If I aggregate the DB, Child B rolls up. However, I'd like to understand why Child A rolls up without the agg, while Child be does not.