We are using xUnit to convert both nUnit & UnitTest++ reports for Jenkins.

I just noticed that the total test duration displayed in Jenkins is invalid. I opened the junitResult.xml file which I guess is generated by xUnit and the duration at the end is definitely wrong.

In my case, the duration shows:
<duration>228.79994</duration>

And there were some test suites that lasted more than that
<suite>
<file>...\generatedJUnitFiles\NUnit\TEST--1009090779.xml</file>
<name>TestContracts</name>
<duration>658.13367</duration>