Debugger 'Trace into' option stopped working in a Package with a Procedure (4269307)

The Trace into option is not working for the debugger. The Package keeps on failing with call stacks stating "Process is not accessible" when attempting to trace into the code.
On the other hand, for testing purposes the following Procedure works with the Trace Into option:

CREATE OR REPLACE PROCEDURE loopproc (inval NUMBER)

IS

tmpvar NUMBER;

tmpvar2 NUMBER;

total NUMBER;

BEGIN

tmpvar := 0;

tmpvar2 := 0;

total := 0;

FOR lcv IN 1 .. inval

LOOP

total := 2 * total + 1 - tmpvar2;

tmpvar2 := tmpvar;

tmpvar := total;

END LOOP;

DBMS_OUTPUT.put_line ('TOTAL IS: ' || total);

END loopproc;
/