diff --git a/gsk/gl/gskglrenderjob.c b/gsk/gl/gskglrenderjob.c
index 570d99665e..d1a581f135 100644
--- a/gsk/gl/gskglrenderjob.c
+++ b/gsk/gl/gskglrenderjob.c
@@ -2445,8 +2445,8 @@ gsk_gl_render_job_visit_blurred_outset_shadow_node (GskGLRenderJob      *job,
                                                     const GskRenderNode *node)
 {
   const GskRoundedRect *outline = gsk_outset_shadow_node_get_outline (node);
-  float scale_x = job->scale_x;
-  float scale_y = job->scale_y;
+  float scale_x = fabsf (job->scale_x);
+  float scale_y = fabsf (job->scale_y);
   float blur_radius = gsk_outset_shadow_node_get_blur_radius (node);
   float blur_extra = blur_radius * 2.0f; /* 2.0 = shader radius_multiplier */
   float half_blur_extra = blur_extra / 2.0f;
@@ -2577,8 +2577,8 @@ gsk_gl_render_job_visit_blurred_outset_shadow_node (GskGLRenderJob      *job,
                                            &offscreen,
                                            texture_width,
                                            texture_height,
-                                           blur_radius * fabsf (scale_x),
-                                           blur_radius * fabsf (scale_y));
+                                           blur_radius * scale_x,
+                                           blur_radius * scale_y);
 
       gsk_gl_shadow_library_insert (job->driver->shadows_library,
                                     &scaled_outline,
diff --git a/gsk/gpu/gskgpunodeprocessor.c b/gsk/gpu/gskgpunodeprocessor.c
index d3bc55cb16..0349abe0bd 100644
--- a/gsk/gpu/gskgpunodeprocessor.c
+++ b/gsk/gpu/gskgpunodeprocessor.c
@@ -2104,7 +2104,7 @@ gsk_gpu_node_processor_add_inset_shadow_node (GskGpuNodeProcessor *self,
   spread = gsk_inset_shadow_node_get_spread (node);
   blur_radius = gsk_inset_shadow_node_get_blur_radius (node);
 
-  if (blur_radius == 0)
+  if (blur_radius < 0.01)
     {
       float color[4]; 
 
@@ -2156,7 +2156,7 @@ gsk_gpu_node_processor_add_outset_shadow_node (GskGpuNodeProcessor *self,
   dx = gsk_outset_shadow_node_get_dx (node);
   dy = gsk_outset_shadow_node_get_dy (node);
 
-  if (blur_radius == 0)
+  if (blur_radius < 0.01)
     {
       GskRoundedRect outline;
       float color[4]; 
diff --git a/gsk/gpu/shaders/gskgpuboxshadow.glsl b/gsk/gpu/shaders/gskgpuboxshadow.glsl
index 5294e0b87d..f74cc78734 100644
--- a/gsk/gpu/shaders/gskgpuboxshadow.glsl
+++ b/gsk/gpu/shaders/gskgpuboxshadow.glsl
@@ -111,14 +111,18 @@ blur_corner (vec2 p,
   if (min (r.x, r.y) <= 0.0)
     return 0.0;
 
+  p /= _sigma;
+  r /= _sigma;
   float result = 0.0;
-  float step = max (1.0, r.y / 8.0);
-  for (float y = 0.5 * step; y <= r.y; y += step)
+  float start = max (p.y - 3.0, 0.0);
+  float end = min (p.y + 3.0, r.y);
+  float step = (end - start) / 7.0;
+  for (float y = start; y <= end; y += step)
     {
       float x = r.x - ellipse_x (r, r.y - y);
-      result -= gauss (p.y - y, _sigma.y) * erf_range (vec2 (- p.x, x - p.x), _sigma.x);
+      result -= gauss (p.y - y, 1.0) * erf_range (vec2 (- p.x, x - p.x), 1.0);
   }
-  return result;
+  return step * result;
 }
 
 float
diff --git a/testsuite/gsk/compare/outset-shadow-corner-blur-huge-nocairo-nogl.node b/testsuite/gsk/compare/outset-shadow-corner-blur-huge-nocairo-nogl.node
new file mode 100644
index 0000000000..054c3d3ce2
--- /dev/null
+++ b/testsuite/gsk/compare/outset-shadow-corner-blur-huge-nocairo-nogl.node
@@ -0,0 +1,10 @@
+clip {
+  clip: 1400 1400 20 20;
+  child: color-matrix {
+    matrix: matrix3d(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255);
+    child: outset-shadow {
+      blur: 1000;
+      outline: 0 0 1000 1000 / 1000 0 1000 0;
+    }
+  }
+}
diff --git a/testsuite/gsk/compare/outset-shadow-corner-blur-huge-nocairo-nogl.png b/testsuite/gsk/compare/outset-shadow-corner-blur-huge-nocairo-nogl.png
new file mode 100644
index 0000000000..02d28f5626
Binary files /dev/null and b/testsuite/gsk/compare/outset-shadow-corner-blur-huge-nocairo-nogl.png differ
diff --git a/testsuite/gsk/compare/outset-shadow-corner-blur-tiny.node b/testsuite/gsk/compare/outset-shadow-corner-blur-tiny.node
new file mode 100644
index 0000000000..a61362eb6d
--- /dev/null
+++ b/testsuite/gsk/compare/outset-shadow-corner-blur-tiny.node
@@ -0,0 +1,11 @@
+color {
+  bounds: 0 0 100 100;
+  color: rgba(0,0,0,0);
+}
+clip {
+  clip: 10 10 20 20;
+  child: outset-shadow {
+    blur: 0.00001;
+    outline: 0 0 100 100 / 100 0 100 0;
+  }
+}
diff --git a/testsuite/gsk/compare/outset-shadow-corner-blur-tiny.png b/testsuite/gsk/compare/outset-shadow-corner-blur-tiny.png
new file mode 100644
index 0000000000..eea25d772f
Binary files /dev/null and b/testsuite/gsk/compare/outset-shadow-corner-blur-tiny.png differ
diff --git a/testsuite/gsk/compare/outset-shadow-corner-blur.node b/testsuite/gsk/compare/outset-shadow-corner-blur.node
new file mode 100644
index 0000000000..ac1bd33bd7
--- /dev/null
+++ b/testsuite/gsk/compare/outset-shadow-corner-blur.node
@@ -0,0 +1,7 @@
+clip {
+  clip: 0 0 15 15;
+  child: outset-shadow {
+    blur: 10;
+    outline: 0 0 100 100 / 100 0 100 0;
+  }
+}
diff --git a/testsuite/gsk/compare/outset-shadow-corner-blur.png b/testsuite/gsk/compare/outset-shadow-corner-blur.png
new file mode 100644
index 0000000000..781abc4fd4
Binary files /dev/null and b/testsuite/gsk/compare/outset-shadow-corner-blur.png differ
diff --git a/testsuite/gsk/meson.build b/testsuite/gsk/meson.build
index dfdf585790..55f6c88726 100644
--- a/testsuite/gsk/meson.build
+++ b/testsuite/gsk/meson.build
@@ -119,6 +119,9 @@ compare_render_tests = [
   'opacity-colormatrix-combinations',
   'opacity-overdraw',
   'opacity-overlapping-children',
+  'outset-shadow-corner-blur',
+  'outset-shadow-corner-blur-huge-nocairo-nogl',
+  'outset-shadow-corner-blur-tiny',
   'outset_shadow_offset_both',
   'outset_shadow_offset_x',
   'outset_shadow_offset_y',