This was changed in a prior PTF for actually release 11.0 SP3, but release 11.6 acts the same way as designed. RO03555 has the following problem description:
When a client tested one of their Easytrieve programs under 11.0 SP3 (and 11.6), if SYSLIN DD DUMMY was coded, a S0C4 abend was issued in EZTGO at +2AA or +2AE.
The fix issues the following new message, and the condition code is set to 0016:
+EZGO0006 CA-EASYTRIEVE UNABLE TO OPEN (EMPTY) SYSLIN FILE.
So, the above PTF resolved a S0C4 abend and now generates the +EZGO0006 message.
Removing the unnecessary //SYSLIN DD DUMMY statement allows JOB06OP1 to run to completion successfully.