When executing code that utilizes format 2 of the STOP statement
STOP "literal statement"
The debugger is invoked at the STOP, but no source code is visible even though the program had been compiled for source level debugging using the "-Ga" or "-GD" switches.
ACUCOBOL-GT Reference Manual Version 8.0
Chapter 6: Procedure Division > 6.6 Procedure Division Statements > STOP statement
A Format 2 STOP literal statement suspends execution of the program and passes control to the ACUCOBOL-GT debugger. The debugger prints the literal on the screen before accepting debugging commands. Note, however, that you cannot do source level debugging unless you compiled with the "-Zd" option and run with the "-d" option.