How to avoid error Perl lib version (5.28.1) doesn't match executable version (5.36.0)

When trying to use clone.pl to clone the latest version of the Oracle 19c database, the following error stopped me from proceeding:

/sw/oracle/product/19.18/clone/bin/clone.pl: 
Perl lib version (5.28.1) doesn't match executable '/sw/oracle/product/19.18/perl/bin/perl' 
version (5.36.0) at /sw/oracle/product/19.17/perl/lib/5.28.1/x86_64-linux-thread-multi/Config.pm 
line 62.

Turns out that that the error occured at the following point in my code:

export NEW_ORACLE_HOME=$ORACLE_BASE/product/19.18
export PRE_ORACLE_HOME=$ORACLE_BASE/product/19.17
export NEW_ORACLE_VERSION=19C_230117
su - oracle <<!
cd $NEW_ORACLE_HOME/clone/bin
perl clone.pl ORACLE_HOME=$NEW_ORACLE_HOME ORACLE_HOME_NAME=$NEW_ORACLE_VERSION ORACLE_BASE=$ORACLE_BASE OSDBA_GROUP=dba
!

Cause:
The .bash_profile of the oracle user contained a variable commonly used in EBS database environments:

export PERL5LIB=/sw/oracle/product/19.17/perl/lib/5.28.1:/sw/oracle/product/19.17/perl/lib/site_perl/5.28.1:/sw/oracle/product/19.17/appsutil/perl

and when trying to run the clone.pl program from the new ORACLE_HOME, perl was unable to find the matching libraries.

Solution:
unset the PERL5LIB before running the clone.pl program:

export NEW_ORACLE_HOME=$ORACLE_BASE/product/19.18
export PRE_ORACLE_HOME=$ORACLE_BASE/product/19.17
export NEW_ORACLE_VERSION=19C_230117
su - oracle <<!
cd $NEW_ORACLE_HOME/clone/bin
unset PERL5LIB
perl clone.pl ORACLE_HOME=$NEW_ORACLE_HOME ORACLE_HOME_NAME=$NEW_ORACLE_VERSION ORACLE_BASE=$ORACLE_BASE OSDBA_GROUP=dba
!