convert2rhel fails with duplicate pkgs installed

Description of problem:

When performing Centos 7.9 to RHEL 7.9 upgrade, conversion fails with

~~~
AssertionError
FATAL ERROR: python callback <bound method RPMTransaction.callback of <yum.rpmtrans.RPMTransaction instance at 0x7f560b659f80>> failed, aborting!
~~~

Version-Release number of selected component (if applicable): convert2rhel-1.2-2.el7.noarch

How reproducible: Only on customer's system.

Steps to Reproduce:
1. Run confirt2rhel

/usr/bin/convert2rhel --org ***** --no-rhsm --enablerepo=susemanager:rhel-7-server-rpms-centos -y

Actual results:

From 'convert2rhel-cd-p-pre-op1.txt'

~~~
Downloading package: zlib-devel-1.2.7-20.el7_9.x86_64.rpm
Running Transaction Check
Traceback (most recent call last):
File "/usr/lib/python2.7/site-packages/yum/rpmtrans.py", line 454, in callback
return self._instOpenFile( bytes, total, h )
File "/usr/lib/python2.7/site-packages/yum/rpmtrans.py", line 500, in _instOpenFile
name, txmbr = self._getTxmbr(h)
File "/usr/lib/python2.7/site-packages/yum/rpmtrans.py", line 280, in _getTxmbr
assert len(txmbrs) == 1
AssertionError
FATAL ERROR: python callback <bound method RPMTransaction.callback of <yum.rpmtrans.RPMTransaction instance at 0x7f9a0496a638>> failed, aborting!
[root@cd-p-pre-op1 ~]#
~~~

Expected results:

convert2rhel to run successfully.

Additional info: