Cannot find files from reports generated in parallel

pipeline {
    stages {
        stage('PythonChecks') {
            steps {
                parallel(
                    some_para_pep8_step: {
                            sh 'pycodestyle src/whmonit || exit 0'
                    },
                )
            }
            post {
                always {
                    warnings(
                        canRunOnFailed: true,
                        categoriesPattern: '',
                        consoleParsers: [[parserName: 'Pep8']],
                        defaultEncoding: '',
                        excludePattern: '',
                        healthy: '1',
                        includePattern: '',
                        messagesPattern: '',
                        unHealthy: '2',
                        unstableTotalAll: '3',
                    )
                }
            }
        }
    }
}

01 Copying the source file '[some_para_pep8_step] src/whmonit/client/agent.py' from the workspace to the build folder '9f0d4020.tmp' on the Jenkins master failed.
02 Seems that the path is relative, however an absolute path is required when copying the sources.
03 Is the file 'agent.py' contained more than once in your workspace?
04 Is the file '[some_para_pep8_step] src/whmonit/client/agent.py' a valid filename?
05 If you are building on a slave: please check if the file is accessible under '$JENKINS_HOME/[job-name]/[some_para_pep8_step] src/whmonit/client/agent.py'
06 If you are building on the master: please check if the file is accessible under '$JENKINS_HOME/[job-name]/workspace/[some_para_pep8_step] src/whmonit/client/agent.py'
07 java.io.IOException: Failed to copy [some_para_pep8_step] src/whmonit/client/agent.py to /var/lib/jenkins/jobs/PM_master_TEST/builds/145/workspace-files/9f0d4020.tmp
08   at hudson.FilePath.copyTo(FilePath.java:2003)
09   at hudson.plugins.analysis.util.Files.copyFilesWithAnnotationsToBuildFolder(Files.java:80)
10   at hudson.plugins.analysis.core.HealthAwareRecorder.copyFilesWithAnnotationsToBuildFolder(HealthAwareRecorder.java:351)
11   at hudson.plugins.analysis.core.HealthAwarePublisher.perform(HealthAwarePublisher.java:91)
12   at hudson.plugins.analysis.core.HealthAwareRecorder.perform(HealthAwareRecorder.java:298)
13   at org.jenkinsci.plugins.workflow.steps.CoreStep$Execution.run(CoreStep.java:80)
14   at org.jenkinsci.plugins.workflow.steps.CoreStep$Execution.run(CoreStep.java:67)
15   at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution$1$1.call(SynchronousNonBlockingStepExecution.java:49)
16   at hudson.security.ACL.impersonate(ACL.java:260)
17   at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution$1.run(SynchronousNonBlockingStepExecution.java:46)
18   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
19   at java.util.concurrent.FutureTask.run(FutureTask.java:266)
20   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
21   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
22   at java.lang.Thread.run(Thread.java:748)
23 Caused by: java.io.IOException: remote file operation failed: [some_para_pep8_step] src/whmonit/client/agent.py at hudson.remoting.Channel@21ac9f5d:cislave2: java.nio.file.NoSuchFileException: [some_para_pep8_step] src/whmonit/client/agent.py
24   at hudson.FilePath.act(FilePath.java:994)
25   at hudson.FilePath.act(FilePath.java:976)
26   at hudson.FilePath.copyTo(FilePath.java:2024)
27   at hudson.FilePath.copyTo(FilePath.java:2000)
28   ... 14 more
29 Caused by: java.nio.file.NoSuchFileException: [some_para_pep8_step] src/whmonit/client/agent.py
30   at sun.nio.fs.UnixException.translateToIOException(UnixException.java:86)
31   at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102)
32   at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107)
33   at sun.nio.fs.UnixFileSystemProvider.newByteChannel(UnixFileSystemProvider.java:214)
34   at java.nio.file.Files.newByteChannel(Files.java:361)
35   at java.nio.file.Files.newByteChannel(Files.java:407)
36   at java.nio.file.spi.FileSystemProvider.newInputStream(FileSystemProvider.java:384)
37   at java.nio.file.Files.newInputStream(Files.java:152)
38   at hudson.FilePath$41.invoke(FilePath.java:2027)
39   at hudson.FilePath$41.invoke(FilePath.java:2024)
40   at hudson.FilePath$FileCallableWrapper.call(FilePath.java:2750)
41   at hudson.remoting.UserRequest.perform(UserRequest.java:181)
42   at hudson.remoting.UserRequest.perform(UserRequest.java:52)
43   at hudson.remoting.Request$2.run(Request.java:336)
44   at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:68)
45   at java.util.concurrent.FutureTask.run(FutureTask.java:266)
46   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
47   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
48   at java.lang.Thread.run(Thread.java:748)
49   at ......remote call to cislave2(Native Method)
50   at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1554)
51   at hudson.remoting.UserResponse.retrieve(UserRequest.java:281)
52   at hudson.remoting.Channel.call(Channel.java:839)
53   at hudson.FilePath.act(FilePath.java:987)
54   ... 17 more