diff --git a/modules/actions/flip.js b/modules/actions/flip.js
index cfb83279a..6b4ef7ffb 100644
--- a/modules/actions/flip.js
+++ b/modules/actions/flip.js
@@ -27,8 +27,10 @@ export function actionFlip(wayId, isVertical, projection) {
             .map(function (nodeId) {
                 return graph.entity(nodeId);
             })
+            // Only process each node once, as the first node will be listed twice in the way
+            .uniqBy(function (node) { return node.id; })
+            // Get distance from midPoint and produce a translated node
             .map(function (node) {
-                // Get distance from midPoint
                 const delta = isVertical ?
                     node.loc[1] - midPoint :
                     node.loc[0] - midPoint;
diff --git a/test/spec/actions/flip.js b/test/spec/actions/flip.js
index 26cbdbf38..925267fbb 100644
--- a/test/spec/actions/flip.js
+++ b/test/spec/actions/flip.js
@@ -21,14 +21,57 @@ describe('iD.actionFlip', function() {
                 iD.Node({id: 'b', loc: [2, 0]}),
                 iD.Node({id: 'c', loc: [2, 2]}),
                 iD.Node({id: 'd', loc: [0, 2]}),
-                                iD.Way({id: '-', nodes: ['a', 'b', 'c', 'd', 'a'], tags: { area: 'yes'}})
+                iD.Way({id: '-', nodes: ['a', 'b', 'c', 'd', 'a'], tags: { area: 'yes'}})
             ]);
         graph = iD.actionFlip('-', false, projection)(graph);
-
-         expect(graph.entity('a').loc[0]).to.equal(2); // A should be 2,0 now
-         expect(graph.entity('b').loc[0]).to.equal(0); // B should be 0,0 now
-         expect(graph.entity('c').loc[0]).to.equal(0); // C should be 0,2 now
-         expect(graph.entity('d').loc[0]).to.equal(2); // D should be 2,0 now
+        expect(graph.entity('a').loc[0]).to.equal(2); // A should be 2,0 now
+        expect(graph.entity('b').loc[0]).to.equal(0); // B should be 0,0 now
+        expect(graph.entity('c').loc[0]).to.equal(0); // C should be 0,2 now
+        expect(graph.entity('d').loc[0]).to.equal(2); // D should be 2,2 now
     });
 
+     it('flips horizontally - does not alter y value', function () {
+        var graph = iD.Graph([
+                iD.Node({id: 'a', loc: [0, 0]}),
+                iD.Node({id: 'b', loc: [2, 0]}),
+                iD.Node({id: 'c', loc: [2, 2]}),
+                iD.Node({id: 'd', loc: [0, 2]}),
+                iD.Way({id: '-', nodes: ['a', 'b', 'c', 'd', 'a'], tags: { area: 'yes'}})
+            ]);
+        graph = iD.actionFlip('-', false, projection)(graph);
+        expect(graph.entity('a').loc[1]).to.equal(0); // A should be 2,0 now
+        expect(graph.entity('b').loc[1]).to.equal(0); // B should be 0,0 now
+        expect(graph.entity('c').loc[1]).to.equal(2); // C should be 0,2 now
+        expect(graph.entity('d').loc[1]).to.equal(2); // D should be 2,2 now
+    });
+
+     it('flips vertically - alters y value', function () {
+        var graph = iD.Graph([
+                iD.Node({id: 'a', loc: [0, 0]}),
+                iD.Node({id: 'b', loc: [2, 0]}),
+                iD.Node({id: 'c', loc: [2, 2]}),
+                iD.Node({id: 'd', loc: [0, 2]}),
+                iD.Way({id: '-', nodes: ['a', 'b', 'c', 'd', 'a'], tags: { area: 'yes'}})
+            ]);
+        graph = iD.actionFlip('-', true, projection)(graph);
+        expect(graph.entity('a').loc[1]).to.equal(2); // A should be 0,2 now
+        expect(graph.entity('b').loc[1]).to.equal(2); // B should be 2,2 now
+        expect(graph.entity('c').loc[1]).to.equal(0); // C should be 2,0 now
+        expect(graph.entity('d').loc[1]).to.equal(0); // D should be 0,0 now
+    });
+
+     it('flips vertically - does not alter x value', function () {
+        var graph = iD.Graph([
+                iD.Node({id: 'a', loc: [0, 0]}),
+                iD.Node({id: 'b', loc: [2, 0]}),
+                iD.Node({id: 'c', loc: [2, 2]}),
+                iD.Node({id: 'd', loc: [0, 2]}),
+                iD.Way({id: '-', nodes: ['a', 'b', 'c', 'd', 'a'], tags: { area: 'yes'}})
+            ]);
+        graph = iD.actionFlip('-', true, projection)(graph);
+        expect(graph.entity('a').loc[0]).to.equal(0); // A should be 0,2 now
+        expect(graph.entity('b').loc[0]).to.equal(2); // B should be 2,2 now
+        expect(graph.entity('c').loc[0]).to.equal(2); // C should be 2,0 now
+        expect(graph.entity('d').loc[0]).to.equal(0); // D should be 0,0 now
+    });
 });