What are the settings for the environment variable ES_INQFILE_RETURN?
Documentation states the following for the environment variable ES_INQFILE_RETURN:-

Modifies EXEC CICS INQUIRE FILE behavior.

Additional information on the settings available is as follows:-

This environment variable can take the value DSN or PCN (dataset or PC name respectively) and will modify the behaviour of INQUIRE FILE's options BASEDSNAME and DSNAME returning the information in the format specified by the variable.

Old KB# 35979