Unable to count as a failures: <system-err> tags

[jrpally]

Jenkins and plugins versions report

Jenkins cannot report <system-err> failures. So they are not visible when jenkins finishes and xml report contains system-err tag. 
Example:

<testcase classname="FunctionalTest" name="test_remove" time="0.476" timestamp="2022-11-28T06:36:09" file="client\functional.py" line="136">
<system-err>
<![CDATA[ C:\jenkins\workspace\client\functional.py:1034: DeprecationWarning: invalid escape sequence '\g' text = out[0].decode('unicode-escape') ]]>
...
</system-err>
...
</testcase>

What Operating System are you using (both controller, and any agents involved in the problem)?

Windows 11

Reproduction steps

Just look reports containing system-err tags and not containing failures.

Report will show all testcases passed which is wrong because should be considered.

Expected Results

Jenkins should be able to recognize system-err tags

Actual Results

system-err tags are not visible on Jenkins

Anything else?

N/A