diff --git a/CHANGES.md b/CHANGES.md
index af1c081c3808..b671e95f76b1 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -8,6 +8,7 @@
 
 - Updated geometric self-shadowing function to improve direct lighting on models using physically-based rendering. [#12063](https://github.com/CesiumGS/cesium/pull/12063)
 - Fixed environment map LOD selection in image-based lighting. [#12070](https://github.com/CesiumGS/cesium/pull/12070)
+- Fixed performance issues with GLTF extension CESIUM_primitive_outline since version 1.96. [#12077](https://github.com/CesiumGS/cesium/issues/12077)
 - Corrected calculation of diffuse component in image-based lighting. [#12082](https://github.com/CesiumGS/cesium/pull/12082)
 
 ### 1.119 - 2024-07-01
diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index 32135cd53279..c75d76aaeab5 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -391,3 +391,4 @@ See [CONTRIBUTING.md](CONTRIBUTING.md) for details on how to contribute to Cesiu
 - [Peter A. Jonsson](https://github.com/pjonsson)
 - [Zhongxiang Wang](https://github.com/plainheart)
 - [Tim Schneider](https://github.com/Tim-S)
+- [朱铭凡](https://github.com/MingFanZhu)
diff --git a/packages/engine/Source/Scene/PrimitiveLoadPlan.js b/packages/engine/Source/Scene/PrimitiveLoadPlan.js
index 31d1f5928f5f..7df391b7f4df 100644
--- a/packages/engine/Source/Scene/PrimitiveLoadPlan.js
+++ b/packages/engine/Source/Scene/PrimitiveLoadPlan.js
@@ -193,6 +193,15 @@ function generateOutlines(loadPlan) {
   indices.typedArray = generator.updatedTriangleIndices;
   indices.indexDatatype = IndexDatatype.fromTypedArray(indices.typedArray);
 
+  // Some vertices may be copied due to the addition of the new attribute
+  // which may have multiple values at a vertex depending on the face
+  const attributePlans = loadPlan.attributePlans;
+  const attributesLength = loadPlan.attributePlans.length;
+  for (let i = 0; i < attributesLength; i++) {
+    const attribute = attributePlans[i].attribute;
+    attribute.typedArray = generator.updateAttribute(attribute.typedArray);
+  }
+
   // The outline generator creates a new attribute for the outline coordinates
   // that are used with a lookup texture.
   const outlineCoordinates = makeOutlineCoordinatesAttribute(
@@ -203,15 +212,6 @@ function generateOutlines(loadPlan) {
   outlineCoordinatesPlan.loadTypedArray = false;
   loadPlan.attributePlans.push(outlineCoordinatesPlan);
   primitive.outlineCoordinates = outlineCoordinatesPlan.attribute;
-
-  // Some vertices may be copied due to the addition of the new attribute
-  // which may have multiple values at a vertex depending on the face
-  const attributePlans = loadPlan.attributePlans;
-  const attributesLength = loadPlan.attributePlans.length;
-  for (let i = 0; i < attributesLength; i++) {
-    const attribute = attributePlans[i].attribute;
-    attribute.typedArray = generator.updateAttribute(attribute.typedArray);
-  }
 }
 
 function makeOutlineCoordinatesAttribute(outlineCoordinatesTypedArray) {