diff --git a/crates/render/src/raster/tests/isolated_cmyk_groups.rs b/crates/render/src/raster/tests/isolated_cmyk_groups.rs
index 44df1a0e45..c9cc9aa492 100644
--- a/crates/render/src/raster/tests/isolated_cmyk_groups.rs
+++ b/crates/render/src/raster/tests/isolated_cmyk_groups.rs
@@ -214,3 +214,69 @@ trailer << /Root 1 0 R >>
     assert!(rgb[2] > 150, "the RGB control shows half-opacity magenta over white, not red: {rgb:?}");
     assert!(rgb.iter().zip(&cmyk).all(|(a, b)| a.abs_diff(*b) <= 3), "CMYK {cmyk:?}, RGB {rgb:?}");
 }
+
+/// A minimal page with `page` as its content, a shading pattern `/P` and an isolated
+/// `DeviceCMYK` group `/G` over `bbox` drawing `group`; the RGB of device pixel (`x`, `y`).
+fn cmyk_group_pixel(media: [u32; 2], page: &str, bbox: [u32; 4], group: &str, group_resources: &str, (x, y): (u32, u32)) -> Vec<u8> {
+    let pdf = format!(
+        "%PDF-1.7
+1 0 obj << /Type /Catalog /Pages 2 0 R >> endobj
+2 0 obj << /Type /Pages /Kids [3 0 R] /Count 1 >> endobj
+3 0 obj << /Type /Page /Parent 2 0 R /MediaBox [0 0 {} {}] /Contents 4 0 R /Resources << /XObject << /G 5 0 R >> /Pattern << /P 6 0 R >> >> >> endobj
+4 0 obj << /Length {} >> stream
+{page}
+endstream endobj
+5 0 obj << /Type /XObject /Subtype /Form /BBox [{} {} {} {}] /Group << /S /Transparency /CS /DeviceCMYK /I true >> /Resources << {group_resources} >> /Length {} >> stream
+{group}
+endstream endobj
+6 0 obj << /Type /Pattern /PatternType 2 /Matrix [2 0 0 2 30 40] /Shading << /ShadingType 2 /ColorSpace /DeviceRGB /Coords [0 0 10 0] /Extend [true true] /Function << /FunctionType 2 /Domain [0 1] /C0 [1 0 0] /C1 [0 0 1] /N 1 >> >> >> endobj
+trailer << /Root 1 0 R >>
+%%EOF",
+        media[0],
+        media[1],
+        page.len(),
+        bbox[0],
+        bbox[1],
+        bbox[2],
+        bbox[3],
+        group.len()
+    );
+    let mut r = PageRenderer::new(Arc::new(pdf.into_bytes()), RenderConfig::default());
+    let p = r.render(RenderRequest { page: 0, kind: RequestKind::Pixels, tile: None, scale: 1.0, tag: 0, ..Default::default() });
+    assert!(p.error.is_none(), "{:?}", p.error);
+    p.rgba[((y * p.width + x) * 4) as usize..][..3].to_vec()
+}
+
+/// From the review of #5228: a shading pattern painted before the group left its pattern
+/// transform on the context, and the finished group was drawn through it, so the cyan half
+/// of the group showed magenta. The group must look the same whether or not a pattern was
+/// painted first.
+#[test]
+fn a_pattern_painted_before_an_isolated_cmyk_group_does_not_move_it() {
+    let group = "0 1 0 0 k 20 20 30 60 re f 1 0 0 0 k 50 20 30 60 re f";
+    let render = |page: &str| cmyk_group_pixel([100, 100], page, [20, 20, 80, 80], group, "", (55, 50));
+    let after_pattern = render("/Pattern cs /P scn 0 0 5 5 re f /G Do");
+    let alone = render("/G Do");
+    assert!(alone[2] > 150 && alone[0] < 100, "the control is cyan: {alone:?}");
+    assert!(alone.iter().zip(&after_pattern).all(|(a, b)| a.abs_diff(*b) <= 3), "after a pattern {after_pattern:?}, alone {alone:?}");
+}
+
+/// From the review of #5228: the Color blend mode over an isolated group's empty backdrop
+/// keeps the source colour (ISO 32000-2 §11.3.5.3 with nothing beneath). The K ink pass
+/// draws gray, and vello_cpu's nonseparable blend of a gray darkened some K levels to
+/// near black. Every 8-bit K level is checked against a plain fill of the same ink.
+#[test]
+fn the_color_blend_mode_over_an_empty_cmyk_group_keeps_every_k_level() {
+    let mut wrong = Vec::new();
+    for level in 0..=255u8 {
+        let k = format!("0 0 0 {} k", f32::from(level) / 255.0);
+        let page = format!("{k} 0 0 20 20 re f /G Do");
+        let group = format!("/B gs {k} 20 0 20 20 re f");
+        let plain = cmyk_group_pixel([40, 20], &page, [20, 0, 40, 20], &group, "/ExtGState << /B << /BM /Color >> >>", (10, 10));
+        let blended = cmyk_group_pixel([40, 20], &page, [20, 0, 40, 20], &group, "/ExtGState << /B << /BM /Color >> >>", (30, 10));
+        if plain.iter().zip(&blended).any(|(a, b)| a.abs_diff(*b) > 3) {
+            wrong.push((level, plain, blended));
+        }
+    }
+    assert!(wrong.is_empty(), "K levels drawn wrong (level, plain, blended): {wrong:?}");
+}
diff --git a/vendor/hayro/src/renderer.rs b/vendor/hayro/src/renderer.rs
index a37df005a0..635cabf349 100644
--- a/vendor/hayro/src/renderer.rs
+++ b/vendor/hayro/src/renderer.rs
@@ -1893,6 +1893,8 @@ impl<'a> Device<'a> for Renderer {
         // must not apply to the finished pixels a second time.
         self.set_soft_mask(None);
         self.set_blend_mode(BlendMode::Normal);
+        // A pattern painted earlier leaves its paint transform on the context.
+        self.ctx.set_paint_transform(Affine::IDENTITY);
         self.draw_pixmap(Arc::new(result), ImageQuality::Low, Affine::translate((x0, y0)));
         true
     }