diff --git a/docs/changelog.md b/docs/changelog.md
index 67704ccd..9da8829d 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -4,6 +4,12 @@
 
 Requires libvips v8.5.5.
 
+#### v0.18.1 - TBD
+
+* Remove regression from #781 that could cause incorrect shrink calculation.
+  [#831](https://github.com/lovell/sharp/issues/831)
+  [@suprMax](https://github.com/suprMax)
+
 #### v0.18.0 - 30<sup>th</sup> May 2017
 
 * Remove the previously-deprecated output format "option" functions:
diff --git a/src/pipeline.cc b/src/pipeline.cc
index 3739df42..d26dbf4a 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -288,7 +288,7 @@ class PipelineWorker : public Nan::AsyncWorker {
         }
       }
       // Help ensure a final kernel-based reduction to prevent shrink aliasing
-      if ((xshrink > 1 || yshrink > 1) && (xresidual == 1.0 || yresidual == 1.0)) {
+      if (xshrink > 1 && yshrink > 1 && (xresidual == 1.0 || yresidual == 1.0)) {
         xshrink = xshrink / 2;
         yshrink = yshrink / 2;
         xresidual = xresidual / 2.0;
diff --git a/test/unit/resize.js b/test/unit/resize.js
index 58aafd47..4664be78 100644
--- a/test/unit/resize.js
+++ b/test/unit/resize.js
@@ -412,4 +412,15 @@ describe('Resize dimensions', function () {
       sharp().resize(32, 24, { centreSampling: 1 });
     });
   });
+
+  it('Dimensions that result in differing shrinks on each axis', function () {
+    return sharp(fixtures.inputJpg)
+      .resize(645, 399)
+      .toBuffer()
+      .then(function (data) {
+        return sharp(data)
+          .resize(150, 100)
+          .toBuffer();
+      });
+  });
 });