When trying to merge a feature branch into trunk we keep getting this error:

ERROR: Step ‘Integrate to upstream upon successful build’ aborted due to exception:
hudson.util.IOException2: Failed to merge
at jenkins.plugins.svnmerge.FeatureBranchProperty$2.invoke(FeatureBranchProperty.java:412)
at jenkins.plugins.svnmerge.FeatureBranchProperty$2.invoke(FeatureBranchProperty.java:292)
at hudson.FilePath.act(FilePath.java:990)
at hudson.FilePath.act(FilePath.java:968)
at jenkins.plugins.svnmerge.FeatureBranchProperty.integrate(FeatureBranchProperty.java:292)
at jenkins.plugins.svnmerge.IntegrateAction.perform(IntegrateAction.java:175)
at jenkins.plugins.svnmerge.IntegrateAction.perform(IntegrateAction.java:165)
at jenkins.plugins.svnmerge.IntegrationPublisher.perform(IntegrationPublisher.java:51)
at hudson.tasks.BuildStepMonitor$2.perform(BuildStepMonitor.java:32)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:782)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:723)
at hudson.model.Build$BuildExecution.post2(Build.java:185)
at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:668)
at hudson.model.Run.execute(Run.java:1763)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:410)
Caused by: org.tmatesoft.svn.core.SVNException: svn: E195016: Cannot merge into a working copy with a switched subtree
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:64)
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:51)
at org.tmatesoft.svn.core.internal.wc2.ng.SvnNgMergeDriver.ensureWcIsSuitableForMerge(SvnNgMergeDriver.java:236)
at org.tmatesoft.svn.core.internal.wc2.ng.SvnNgMergeReintegrate.merge(SvnNgMergeReintegrate.java:107)
at org.tmatesoft.svn.core.internal.wc2.ng.SvnNgMergeReintegrate.run(SvnNgMergeReintegrate.java:65)
at org.tmatesoft.svn.core.internal.wc2.ng.SvnNgMergeReintegrate.run(SvnNgMergeReintegrate.java:45)
at org.tmatesoft.svn.core.internal.wc2.ng.SvnNgOperationRunner.run(SvnNgOperationRunner.java:20)
at org.tmatesoft.svn.core.internal.wc2.SvnOperationRunner.run(SvnOperationRunner.java:21)
at org.tmatesoft.svn.core.wc2.SvnOperationFactory.run(SvnOperationFactory.java:1235)
at org.tmatesoft.svn.core.wc2.SvnOperation.run(SvnOperation.java:294)
at org.tmatesoft.svn.core.wc.SVNDiffClient.doMergeReIntegrate(SVNDiffClient.java:2632)
at jenkins.plugins.svnmerge.FeatureBranchProperty$2.invoke(FeatureBranchProperty.java:346)
... 16 more

The project is up to date for rebaseing:

Rebasing is in progress

Updating workspace to the latest revision
At revision 29259

Merging change from the upstream https://****/svn/marketforce1_lf1/trunk at rev.29258
Committing changes
No changes since the last rebase. This rebase was a no-op.
Completed