diff --git a/src/core/default_appearance.js b/src/core/default_appearance.js
index 6b36572d6..888cb33e1 100644
--- a/src/core/default_appearance.js
+++ b/src/core/default_appearance.js
@@ -154,7 +154,7 @@ class AppearanceStreamEvaluator extends EvaluatorPreprocessor {
               result.fontName = fontName.name;
             }
             if (typeof fontSize === "number" && fontSize > 0) {
-              result.fontSize = fontSize * result.scaleFactor;
+              result.fontSize = fontSize;
             }
             break;
           case OPS.setFillColorSpace:
@@ -184,6 +184,10 @@ class AppearanceStreamEvaluator extends EvaluatorPreprocessor {
           case OPS.showSpacedText:
           case OPS.nextLineShowText:
           case OPS.nextLineSetSpacingShowText:
+            // The font (Tf) and the text matrix (Tm) can be set in any order,
+            // so the scale factor is applied here, when text is actually shown
+            // and both are known to be in effect.
+            result.fontSize *= result.scaleFactor;
             breakLoop = true;
             break;
         }
diff --git a/test/integration/freetext_editor_spec.mjs b/test/integration/freetext_editor_spec.mjs
index 35f10c542..28240b5ac 100644
--- a/test/integration/freetext_editor_spec.mjs
+++ b/test/integration/freetext_editor_spec.mjs
@@ -1876,6 +1876,49 @@ describe("FreeText Editor", () => {
     });
   });
 
+  describe("FreeText (open existing generated with Skia)", () => {
+    let pages;
+
+    beforeEach(async () => {
+      pages = await loadAndWait(
+        "issue20504_skia.pdf",
+        ".annotationEditorLayer",
+        100
+      );
+    });
+
+    afterEach(async () => {
+      await closePages(pages);
+    });
+
+    it("must extract the font size when Tf comes before Tm", async () => {
+      await Promise.all(
+        pages.map(async ([browserName, page]) => {
+          const id = "24R";
+          await page.waitForSelector(getAnnotationSelector(id), {
+            visible: true,
+          });
+
+          await switchToFreeText(page);
+
+          // The Skia appearance stream sets the font (Tf) before the text
+          // matrix (Tm), and the text matrix is scaled by 0.5 through a cm
+          // operator: 20 * 0.5 = 10.
+          const fontSize = await page.evaluate(() => {
+            const editorDiv = document.getElementById(
+              `pdfjs_internal_editor_0-editor`
+            );
+            const match = editorDiv?.style.fontSize.match(/calc\((\d+)px/);
+            return match ? parseInt(match[1], 10) : 0;
+          });
+          expect(fontSize)
+            .withContext(`In ${browserName}, editor 0 fontSize`)
+            .toEqual(10);
+        })
+      );
+    });
+  });
+
   describe("Keyboard shortcuts when the editor layer isn't focused", () => {
     let pages;
 
diff --git a/test/pdfs/.gitignore b/test/pdfs/.gitignore
index a7b875122..54d04c8cf 100644
--- a/test/pdfs/.gitignore
+++ b/test/pdfs/.gitignore
@@ -941,3 +941,4 @@
 !multimedia_annotations.pdf
 !issue17333.pdf
 !issue20504.pdf
+!issue20504_skia.pdf
diff --git a/test/pdfs/issue20504_skia.pdf b/test/pdfs/issue20504_skia.pdf
new file mode 100644
index 000000000..ab5dd609c
Binary files /dev/null and b/test/pdfs/issue20504_skia.pdf differ