Problem:

The FaultFinder log files are missing ALL call stack entries for both COBOL and non-COBOL on AIX.

Resolution:

This appears to be a problem specific to AIX.  To get the call stack entries into the FaultFinder log you need to set the LDR_CNTRL environment variable as follows:

export LDR_CNTRL=USERREGS

Specifying the USERREGS option will tell the system to save all general-purpose user registers across system calls made by an application.