With XUnit Release 3.1.0 working Jenkins pipelines which generates an XML report parsed by xunit with BoostTest are failing with Release 3.1.1 right now.

With XUnit Release 3.1.0 there are no issues.

Log (see attached xml file):

 
INFO: Processing BoostTest-1.x (default)
INFO: [BoostTest-1.x (default)] - 1 test report file(s) were found with the pattern 'components-qt/core/TestLogToXML/TestResultIOS.xml' relative to '/var/jenkins_home/workspace/APP_Android_Release_Branch_1_8_0' for the testing framework 'BoostTest-1.x (default)'.
WARNING: The converted file for the input file '/var/jenkins_home/workspace/APP_Android_Release_Branch_1_8_0/components-qt/core/TestLogToXML/TestResultIOS.xml' doesnt match the JUnit format.
WARNING: At line 31 of file:/var/jenkins_home/workspace/APP_Android_Release_Branch_1_8_0/generatedJUnitFiles/18c04b30-8ccb-43b0-a298-44dda3c3b258/BoostTest/TEST-7de3bac9-c1bf-48a0-a4ea-4a05318c61cb.xml:The markup in the document following the root element must be well-formed.
WARNING: Technical validation:The markup in the document following the root element must be well-formed.
ERROR: The markup in the document following the root element must be well-formed.
ERROR: The markup in the document following the root element must be well-formed.

What is wrong here?