Problem when generating JUnit report on Jenkins Pipeline
From checking the code at: https://github.com/SAP/jenkins-library/blob/5c13a0e2a20132336824c70b743c364bcb5341f4/vars/testsPublishResults.groovy#L136
Looks like you can avoid the issue by setting updateResults to false
If you absolutely have to update the timestamp on the result file, you'll have to open a terminal session, go to the project workspace (with jenkins user) and try to run touch ./reports/mocha.xml and then debug it from there.