When the plugin comes across embeddings I believe it is failing to write out the files to the temporary folder, then the plugin fails to copy the embed files from the temporary folder with the following exception (The location was checked and no files matching the pattern cuke_* were found in that location):

Also:   hudson.remoting.Channel$CallSiteStackTrace: Remote call to BUILD_MACHINE_1
        at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1737)
        at hudson.remoting.UserResponse.retrieve(UserRequest.java:313)
        at hudson.remoting.Channel.call(Channel.java:952)
        at hudson.FilePath.act(FilePath.java:998)
        at hudson.FilePath.act(FilePath.java:987)
        at hudson.FilePath.copyTo(FilePath.java:2079)
        at hudson.FilePath.copyTo(FilePath.java:2040)
        at org.jenkinsci.plugins.cucumber.jsontestsupport.CucumberTestResultArchiver.publishReport(CucumberTestResultArchiver.java:158)
        at org.jenkinsci.plugins.cucumber.jsontestsupport.CucumberTestResultArchiver.perform(CucumberTestResultArchiver.java:119)
        at org.jenkinsci.plugins.workflow.steps.CoreStep$Execution.run(CoreStep.java:80)
        at org.jenkinsci.plugins.workflow.steps.CoreStep$Execution.run(CoreStep.java:67)
        at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution$1$1.call(SynchronousNonBlockingStepExecution.java:49)
        at hudson.security.ACL.impersonate(ACL.java:290)
        at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution$1.run(SynchronousNonBlockingStepExecution.java:46)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
java.nio.file.NoSuchFileException: /data/jenkins/workspace/buildx/~/tmp/cuke_8339765699205404139.embed
    at sun.nio.fs.UnixException.translateToIOException(UnixException.java:86)
    at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102)
    at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107)
    at sun.nio.fs.UnixFileSystemProvider.newByteChannel(UnixFileSystemProvider.java:214)
    at java.nio.file.Files.newByteChannel(Files.java:361)
    at java.nio.file.Files.newByteChannel(Files.java:407)
    at java.nio.file.spi.FileSystemProvider.newInputStream(FileSystemProvider.java:384)
    at java.nio.file.Files.newInputStream(Files.java:152)
    at hudson.FilePath$41.invoke(FilePath.java:2082)
    at hudson.FilePath$41.invoke(FilePath.java:2079)
    at hudson.FilePath$FileCallableWrapper.call(FilePath.java:2816)
    at hudson.remoting.UserRequest.perform(UserRequest.java:210)
    at hudson.remoting.UserRequest.perform(UserRequest.java:53)
    at hudson.remoting.Request$2.run(Request.java:364)
    at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused: java.io.IOException: remote file operation failed: /data/jenkins/workspace/buildx/~/tmp/cuke_8339765699205404139.embed at hudson.remoting.Channel@f06fbf0:BUILD_MACHINE_1
    at hudson.FilePath.act(FilePath.java:1005)
    at hudson.FilePath.act(FilePath.java:987)
    at hudson.FilePath.copyTo(FilePath.java:2079)
    at hudson.FilePath.copyTo(FilePath.java:2040)
Also:       Also:   hudson.remoting.Channel$CallSiteStackTrace: Remote call to BUILD_MACHINE_2
            at hudson.remoting.Channel.attachCallSiteStackTrace(Channel.java:1737)
            at hudson.remoting.UserResponse.retrieve(UserRequest.java:313)
            at hudson.remoting.Channel.call(Channel.java:952)
            at hudson.FilePath.act(FilePath.java:998)
            at hudson.FilePath.act(FilePath.java:987)
            at hudson.FilePath.copyTo(FilePath.java:2079)
            at hudson.FilePath.copyTo(FilePath.java:2040)
            at org.jenkinsci.plugins.cucumber.jsontestsupport.CucumberTestResultArchiver.publishReport(CucumberTestResultArchiver.java:158)
            at org.jenkinsci.plugins.cucumber.jsontestsupport.CucumberTestResultArchiver.perform(CucumberTestResultArchiver.java:119)
            at org.jenkinsci.plugins.workflow.steps.CoreStep$Execution.run(CoreStep.java:80)
            at org.jenkinsci.plugins.workflow.steps.CoreStep$Execution.run(CoreStep.java:67)
            at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution$1$1.call(SynchronousNonBlockingStepExecution.java:49)
            at hudson.security.ACL.impersonate(ACL.java:290)
            at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution$1.run(SynchronousNonBlockingStepExecution.java:46)
            at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
            at java.util.concurrent.FutureTask.run(FutureTask.java:266)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
            at java.lang.Thread.run(Thread.java:745)
java.nio.file.NoSuchFileException: /data/jenkins/workspace/buildx/~/tmp/cuke_6932087206597534508.embed
        at sun.nio.fs.UnixException.translateToIOException(UnixException.java:86)
        at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:102)
        at sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:107)
        at sun.nio.fs.UnixFileSystemProvider.newByteChannel(UnixFileSystemProvider.java:214)
        at java.nio.file.Files.newByteChannel(Files.java:361)
        at java.nio.file.Files.newByteChannel(Files.java:407)
        at java.nio.file.spi.FileSystemProvider.newInputStream(FileSystemProvider.java:384)
        at java.nio.file.Files.newInputStream(Files.java:152)
        at hudson.FilePath$41.invoke(FilePath.java:2082)
        at hudson.FilePath$41.invoke(FilePath.java:2079)
        at hudson.FilePath$FileCallableWrapper.call(FilePath.java:2816)
        at hudson.remoting.UserRequest.perform(UserRequest.java:210)
        at hudson.remoting.UserRequest.perform(UserRequest.java:53)
        at hudson.remoting.Request$2.run(Request.java:364)
        at hudson.remoting.InterceptingExecutorService$1.call(InterceptingExecutorService.java:72)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
    Caused: java.io.IOException: remote file operation failed: /data/jenkins/workspace/buildx/~/tmp/cuke_6932087206597534508.embed at hudson.remoting.Channel@deb5991:BUILD_MACHINE_2
        at hudson.FilePath.act(FilePath.java:1005)
        at hudson.FilePath.act(FilePath.java:987)
        at hudson.FilePath.copyTo(FilePath.java:2079)
        at hudson.FilePath.copyTo(FilePath.java:2040)
    Caused: java.io.IOException: Failed to copy /data/jenkins/workspace/buildx/~/tmp/cuke_6932087206597534508.embed to /var/lib/jenkins/jobs/Pathfinder/jobs/buildx/branches/branch1/builds/490/cucumber/embed/feature2/scenario2;;2/cuke_6932087206597534508.embed
Caused: java.io.IOException: Failed to copy /data/jenkins/workspace/buildx/~/tmp/cuke_8339765699205404139.embed to /var/lib/jenkins/jobs/Pathfinder/jobs/buildx/branches/branch1/builds/490/cucumber/embed/feature1/scenario1./cuke_8339765699205404139.embed
    at hudson.FilePath.copyTo(FilePath.java:2043)
    at org.jenkinsci.plugins.cucumber.jsontestsupport.CucumberTestResultArchiver.publishReport(CucumberTestResultArchiver.java:158)
    at org.jenkinsci.plugins.cucumber.jsontestsupport.CucumberTestResultArchiver.perform(CucumberTestResultArchiver.java:119)
    at org.jenkinsci.plugins.workflow.steps.CoreStep$Execution.run(CoreStep.java:80)
    at org.jenkinsci.plugins.workflow.steps.CoreStep$Execution.run(CoreStep.java:67)
    at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution$1$1.call(SynchronousNonBlockingStepExecution.java:49)
    at hudson.security.ACL.impersonate(ACL.java:290)
    at org.jenkinsci.plugins.workflow.steps.SynchronousNonBlockingStepExecution$1.run(SynchronousNonBlockingStepExecution.java:46)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

I couldnt find any reference in the log to an exception being thrown by GerkinCallback.embedding(....), which I was expecting if it failed to write out the temporary file.