PostgreSQL JDBC 42.7.5 returns an unexpected catalog name

1) Problem Description:
When upgrading our application to a new PostgreSQL JDBC driver 42.7.5 (from 42.7.4), we got an expected catalog name in
theresult set returned by DatabaseMetadata.getSchemas(). 

Expected catalog name:  null (42.7.4)
Unexpected catalog name:  dbcert (42.7.5)

2) Connection Info:
URL used:
jdbc:postgresql://cteds721.fyre.ibm.com:54172/dbcert

Driver name/Version:
org.postgresql.Driver/postgresql-42.7.5.jar

userID/pw: dbcert1/***********

3) Attachements:
a) PG_JDBC_42_7_4.PNG:  Screenshot showing an expected catalog name (null) with driver version 42.7.4.
b) PG_JDBC_42_7_5.PNG:  Screenshot showing an unexpected catalog name (dbcert) with driver version 42.7.5.
c) ImportTest.java:  Java test program used in (a) and (b).

If you need any additional details, please let me know.

Thank you in advance!
Vinhson Nguyen