diff --git a/CHANGELOG b/CHANGELOG
index 3883037339..2f85d7aa10 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -10,6 +10,8 @@ git-annex (6.20180927) UNRELEASED; urgency=medium
   * SETURLPRESENT, SETURIPRESENT, SETURLMISSING, and SETURIMISSING
     used to update the presence information of the external special remote
     that called them; this was not documented behavior and is no longer done.
+  * export: Fix false positive in export conflict detection, that occurred
+    when the same tree was exported by multiple clones.
 
  -- Joey Hess <id@joeyh.name>  Thu, 27 Sep 2018 15:27:20 -0400
 
diff --git a/Command/Export.hs b/Command/Export.hs
index 4c9dbadfb2..1434835ae7 100644
--- a/Command/Export.hs
+++ b/Command/Export.hs
@@ -113,7 +113,7 @@ changeExport r ea db new = do
 	-- When there was an export conflict, this resolves it.
 	--
 	-- The ExportTree is also updated here to reflect the new tree.
-	case map exportedTreeish old of
+	case nub (map exportedTreeish old) of
 		[] -> updateExportTree db emptyTree new
 		[oldtreesha] -> do
 			diffmap <- mkDiffMap oldtreesha new db