SQL*Plus 12.2 and searching path of login.sql

Having installed Oracle Database 12.2 on a client, I have noticed that the login.sql script, which is placed in a custom directory specified by SQLPATH, is not invoked anymore.
Here is my login.sql:

[oracle@localhost]$ cat /tmp/sqlpath/login.sql 
select 'login.sql invoked' output 
  from dual;

The login.sql script is not invoked when I connect through SQL*Plus 12.2 despite the fact the SQLPATH environment variable is set:

[oracle@localhost]$ export SQLPATH=/tmp/sqlpath
[oracle@localhost]$ sqlplus tc/tc@ora12

SQL*Plus: Release 12.2.0.1.0 Production on Wed Mar 15 09:20:52 2017

Copyright (c) 1982, 2016, Oracle.  All rights reserved.

Last Successful login time: Wed Mar 15 2017 09:16:06 +07:00

Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP, Advanced Analytics,
Real Application Testing and Unified Auditing options

SQL> 

This issue is documented in SQL*Plus 12.2.0.1.0 Change in Behavior for Search Path of Login.sql (SQL*Plus User Profile Script) (Doc ID 2241021.1).
Unsurprisignly, if I set ORACLE_PATH, then login.sql is invoked:

[oracle@localhost]$ export ORACLE_PATH=$SQLPATH
[oracle@localhost]$ unset SQLPATH
[oracle@localhost]$ sqlplus tc/tc@ora12

SQL*Plus: Release 12.2.0.1.0 Production on Wed Mar 15 09:21:13 2017

Copyright (c) 1982, 2016, Oracle.  All rights reserved.

Last Successful login time: Wed Mar 15 2017 09:20:52 +07:00

Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP, Advanced Analytics,
Real Application Testing and Unified Auditing options


OUTPUT
---------------------------------------------------
login.sql invoked

SQL> 

The MOS note also contains information that this new behaviour may influence earlier releases when the PSU or CI are released for them.
I have no idea why Oracle has changed the existing functionality with login.sql, but that is definitely something to keep in mind in case you are going to upgrade to a new release.
Interestingly, SQLcl still honor SQLPATH even when both SQLPATH and ORACLE_PATH are set:

[oracle@localhost]$ cat /tmp/sqlpath/login.sql
select 'login.sql invoked' output 
  from dual;
[oracle@localhost]$ cat /tmp/oracle_path/login.sql
select 'oracle_path invoked'
  from dual;
[oracle@localhost]$ export ORACLE_PATH=/tmp/oracle_path
[oracle@localhost]$ export SQLPATH=/tmp/sqlpath
[oracle@localhost]$ ./sql tc/tc@ora12

SQLcl: Release 12.2.0.1.0 RC on Ср мар 15 09:42:08 2017

Copyright (c) 1982, 2017, Oracle.  All rights reserved.

Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, Automatic Storage Management, OLAP, Advanced Analytics,
Real Application Testing and Unified Auditing options


OUTPUT           
-----------------
login.sql invoked