When choosing to load the Workflow Groovy Script direct from the SCM (the Groovy CPS DSL from SCM definition option) the following error occurs:

RTC : checkout...
RTC Checkout : Source control setup
RTC Checkout : Accepting changes into workspace "xxx-main-jenkins-pipeline" ...
RTC Checkout : Fetching files to fetch destination "/mnt/workspace/XXX-Docker-Workflow@script" ...
FATAL: RTC : checkout failure: Failed to create /mnt/workspace/XXX-Docker-Workflow@script/.jazz5
Failed to create /mnt/workspace/XXX-Docker-Workflow@script/.jazz5

com.ibm.team.build.internal.scm.SourceControlUtility$3: Status INFO: com.ibm.team.filesystem.client code=0 Failed to create /mnt/workspace/XXX-Docker-Workflow@script/.jazz5 null
at com.ibm.team.build.internal.scm.SourceControlUtility.updateFileCopyArea(SourceControlUtility.java:693)
at com.ibm.team.build.internal.hjplugin.rtc.RepositoryConnection.checkout(RepositoryConnection.java:440)
at com.ibm.team.build.internal.hjplugin.rtc.RTCFacade.checkout(RTCFacade.java:393)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.ibm.team.build.internal.hjplugin.RTCFacadeFactory$RTCFacadeWrapper.invoke(RTCFacadeFactory.java:115)
at com.ibm.team.build.internal.hjplugin.RTCCheckoutTask.invoke(RTCCheckoutTask.java:165)
at com.ibm.team.build.internal.hjplugin.RTCCheckoutTask.invoke(RTCCheckoutTask.java:31)
at hudson.FilePath.act(FilePath.java:989)
at hudson.FilePath.act(FilePath.java:967)
at com.ibm.team.build.internal.hjplugin.RTCScm.checkout(RTCScm.java:1107)
at org.jenkinsci.plugins.workflow.steps.scm.SCMStep.checkout(SCMStep.java:106)
at org.jenkinsci.plugins.workflow.cps.CpsScmFlowDefinition.create(CpsScmFlowDefinition.java:109)
at org.jenkinsci.plugins.workflow.cps.CpsScmFlowDefinition.create(CpsScmFlowDefinition.java:58)
at org.jenkinsci.plugins.workflow.job.WorkflowRun.run(WorkflowRun.java:183)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:374)
FATAL: RTC : checkout failure: RTC : checkout failure: Failed to create /mnt/workspace/XXX-Docker-Workflow@script/.jazz5
Failed to create /mnt/workspace/XXX-Docker-Workflow@script/.jazz5

It looks like an error in the RTC client that fails to create the file location

The options configured are:

"Just accept and fetch from a build workspace"