diff --git a/gfx/thebes/gfxUserFontSet.cpp b/gfx/thebes/gfxUserFontSet.cpp
index 302ffa8913c..a1acf253188 100644
--- a/gfx/thebes/gfxUserFontSet.cpp
+++ b/gfx/thebes/gfxUserFontSet.cpp
@@ -178,8 +178,15 @@ public:
         : mUserFontEntry(aUserFontEntry) {}
 
     virtual ots::TableAction GetTableAction(uint32_t aTag) override {
-        // preserve Graphite, color glyph and SVG tables
-        if (aTag == TRUETYPE_TAG('S', 'i', 'l', 'f') ||
+        // Preserve Graphite, color glyph and SVG tables
+        if (
+#ifdef RELEASE_BUILD // For Beta/Release, also allow OT Layout tables through
+                     // unchecked, and rely on harfbuzz to handle them safely.
+            aTag == TRUETYPE_TAG('G', 'D', 'E', 'F') ||
+            aTag == TRUETYPE_TAG('G', 'P', 'O', 'S') ||
+            aTag == TRUETYPE_TAG('G', 'S', 'U', 'B') ||
+#endif
+            aTag == TRUETYPE_TAG('S', 'i', 'l', 'f') ||
             aTag == TRUETYPE_TAG('S', 'i', 'l', 'l') ||
             aTag == TRUETYPE_TAG('G', 'l', 'o', 'c') ||
             aTag == TRUETYPE_TAG('G', 'l', 'a', 't') ||