After fix of bug 1670369, test for bug 967510 is now failing with two of the 6 original reproducers (attached).

# rpm -q redhat-support-lib-python
redhat-support-lib-python-0.10.1-1.el8.noarch
# cat >reporthelper.py
#!/bin/env python3

import os
import sys
import redhat_support_lib.utils.reporthelper as reporthelper

if len(sys.argv) == 2:
    file_name = reporthelper.make_report(path=sys.argv[1], report_dir=os.getcwd())
    print('File is %s' % (file_name))
else:
    print("Usage: %s /path/to/file-or-dir" % (sys.argv[0]))

# echo "Hello world." >  hello.txt
# chmod +x reporthelper.py 

# ./reporthelper.py reproducer5.xml 
'_io.StringIO' object has no attribute 'buf'
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/redhat_support_lib/utils/reporthelper.py", line 254, in _write_report_file
    info.size = len(content_xml.buf)
AttributeError: '_io.StringIO' object has no attribute 'buf'
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/redhat_support_lib/utils/reporthelper.py", line 254, in _write_report_file
    info.size = len(content_xml.buf)
AttributeError: '_io.StringIO' object has no attribute 'buf'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./reporthelper.py", line 8, in <module>
    file_name = reporthelper.make_report(path=sys.argv[1], report_dir=os.getcwd())
  File "/usr/lib/python3.6/site-packages/redhat_support_lib/utils/reporthelper.py", line 352, in make_report
    tar_refs)
  File "/usr/lib/python3.6/site-packages/redhat_support_lib/utils/reporthelper.py", line 282, in _write_report_file
    raise Exception('Unable to create report file in %s.' % (temp_dir))
Exception: Unable to create report file in /root/tmphe8soq1o.

# ./reporthelper.py reproducer6.xml.gz 
'_io.StringIO' object has no attribute 'buf'
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/redhat_support_lib/utils/reporthelper.py", line 254, in _write_report_file
    info.size = len(content_xml.buf)
AttributeError: '_io.StringIO' object has no attribute 'buf'
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/redhat_support_lib/utils/reporthelper.py", line 254, in _write_report_file
    info.size = len(content_xml.buf)
AttributeError: '_io.StringIO' object has no attribute 'buf'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./reporthelper.py", line 8, in <module>
    file_name = reporthelper.make_report(path=sys.argv[1], report_dir=os.getcwd())
  File "/usr/lib/python3.6/site-packages/redhat_support_lib/utils/reporthelper.py", line 352, in make_report
    tar_refs)
  File "/usr/lib/python3.6/site-packages/redhat_support_lib/utils/reporthelper.py", line 282, in _write_report_file
    raise Exception('Unable to create report file in %s.' % (temp_dir))
Exception: Unable to create report file in /root/tmpmlkmyziw.