Error calculating auto-merge path

2014-06-20 17:06:48,536 ERROR [http-bio-7990-exec-2304] xxxxxxx 1026x145378x2 10zrerl 10.69.10.134 "GET /rest/branch-utils/latest/projects/XX/repos/automatic-branch-merging/automerge/path HTTP/1.1" c.a.s.r.e.UnhandledExceptionMapper Unhandled exception while processing REST call
java.lang.IllegalStateException: To node InternalBranch{id=refs/heads/release/4.0.x, displayId=release/4.0.x, latestChangeset=0529f68cf8652c268adf03759eb49770747a4d0d, default=true} is already in the graph
	at com.atlassian.stash.internal.branch.model.BranchModelGraphBuilder.addPath(BranchModelGraphBuilder.java:51) ~[stash-branch-utils-2.12.2_1398817592000.jar:na]
	at com.atlassian.stash.internal.branch.model.BranchModelGraphBuilder.forSinglePath(BranchModelGraphBuilder.java:40) ~[stash-branch-utils-2.12.2_1398817592000.jar:na]
	at com.atlassian.stash.internal.branch.model.SimpleBranchModel.getMergePath(SimpleBranchModel.java:77) ~[stash-branch-utils-2.12.2_1398817592000.jar:na]
	at com.atlassian.stash.internal.branch.automerge.DefaultAutoMergeService$$anonfun$getDownstreamBranches$2.apply(DefaultAutoMergeService.scala:44) ~[stash-branch-utils-2.12.2_1398817592000.jar:na]
	at com.atlassian.stash.internal.branch.automerge.DefaultAutoMergeService$$anonfun$getDownstreamBranches$2.apply(DefaultAutoMergeService.scala:44) ~[stash-branch-utils-2.12.2_1398817592000.jar:na]
	at scala.util.Either$RightProjection.map(Either.scala:536) ~[scala-2.10-provider-plugin-0.5.jar:na]
	at com.atlassian.stash.internal.branch.automerge.DefaultAutoMergeService.getDownstreamBranches(DefaultAutoMergeService.scala:44) ~[stash-branch-utils-2.12.2_1398817592000.jar:na]
	at com.atlassian.stash.internal.branch.automerge.DefaultAutoMergeService.getAutoMerge(DefaultAutoMergeService.scala:16) ~[stash-branch-utils-2.12.2_1398817592000.jar:na]
	at com.atlassian.stash.internal.branch.automerge.rest.AutoMergeResource.getMergePath(AutoMergeResource.java:59) ~[stash-branch-utils-2.12.2_1398817592000.jar:na]
	at com.atlassian.applinks.core.rest.context.ContextFilter.doFilter(ContextFilter.java:25) [applinks-plugin-4.1.1_1398817314000.jar:na]
	at com.atlassian.stash.internal.spring.security.StashAuthenticationFilter.doFilter(StashAuthenticationFilter.java:92) [StashAuthenticationFilter.class:na]
	at com.atlassian.stash.internal.web.auth.BeforeLoginPluginAuthenticationFilter.doInsideSpringSecurityChain(BeforeLoginPluginAuthenticationFilter.java:111) [BeforeLoginPluginAuthenticationFilter.class:na]
	at com.atlassian.stash.internal.web.auth.BeforeLoginPluginAuthenticationFilter.doFilter(BeforeLoginPluginAuthenticationFilter.java:77) [BeforeLoginPluginAuthenticationFilter.class:na]
	at com.atlassian.security.auth.trustedapps.filter.TrustedApplicationsFilter.doFilter(TrustedApplicationsFilter.java:100) [atlassian-trusted-apps-core-3.0.3.jar:na]
	at com.atlassian.oauth.serviceprovider.internal.servlet.OAuthFilter.doFilter(OAuthFilter.java:61) [atlassian-oauth-service-provider-plugin-1.9.1_1398817314000.jar:na]
	at com.atlassian.stash.internal.web.auth.BeforeLoginPluginAuthenticationFilter.doBeforeBeforeLoginFilters(BeforeLoginPluginAuthenticationFilter.java:89) [BeforeLoginPluginAuthenticationFilter.class:na]
	at com.atlassian.stash.internal.web.auth.BeforeLoginPluginAuthenticationFilter.doFilter(BeforeLoginPluginAuthenticationFilter.java:75) [BeforeLoginPluginAuthenticationFilter.class:na]
	at com.atlassian.stash.internal.request.DefaultRequestManager.doAsRequest(DefaultRequestManager.java:73) [stash-service-impl-2.12.2.jar:na]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) [na:1.7.0_09-icedtea]
	at java.lang.Thread.run(Thread.java:722) [na:1.7.0_09-icedtea]
	... 178 frames trimmed