diff --git a/packages/dev/core/src/Collisions/gpuPicker.ts b/packages/dev/core/src/Collisions/gpuPicker.ts
index bc523b2d4b3..e0fe7b17373 100644
--- a/packages/dev/core/src/Collisions/gpuPicker.ts
+++ b/packages/dev/core/src/Collisions/gpuPicker.ts
@@ -219,8 +219,6 @@ export class GPUPicker {
             return;
         }
 
-        this._pickableMeshes = list as Array<AbstractMesh>;
-
         // Prepare target
         const scene = ("mesh" in list[0] ? list[0].mesh : list[0]).getScene();
         if (!this._cachedScene || this._cachedScene !== scene) {
diff --git a/packages/dev/core/src/Shaders/picking.fragment.fx b/packages/dev/core/src/Shaders/picking.fragment.fx
index 798024bc86d..9b1214e2a1a 100644
--- a/packages/dev/core/src/Shaders/picking.fragment.fx
+++ b/packages/dev/core/src/Shaders/picking.fragment.fx
@@ -1,6 +1,6 @@
 
 #if defined(INSTANCES)
-varying float vMeshID;
+flat varying float vMeshID;
 #else
 uniform float meshID;
 #endif
diff --git a/packages/dev/core/src/Shaders/picking.vertex.fx b/packages/dev/core/src/Shaders/picking.vertex.fx
index c792eef889b..cf921bc506f 100644
--- a/packages/dev/core/src/Shaders/picking.vertex.fx
+++ b/packages/dev/core/src/Shaders/picking.vertex.fx
@@ -16,7 +16,7 @@ uniform mat4 viewProjection;
 
 // Output
 #if defined(INSTANCES)
-varying float vMeshID;
+flat varying float vMeshID;
 #endif
 
 void main(void) {
diff --git a/packages/dev/core/src/ShadersWGSL/picking.fragment.fx b/packages/dev/core/src/ShadersWGSL/picking.fragment.fx
index 9f7176bb9a1..1eb7550c65f 100644
--- a/packages/dev/core/src/ShadersWGSL/picking.fragment.fx
+++ b/packages/dev/core/src/ShadersWGSL/picking.fragment.fx
@@ -1,6 +1,6 @@
 
 #if defined(INSTANCES)
-varying vMeshID: f32;
+flat varying vMeshID: f32;
 #else
 uniform meshID: f32;
 #endif
diff --git a/packages/dev/core/src/ShadersWGSL/picking.vertex.fx b/packages/dev/core/src/ShadersWGSL/picking.vertex.fx
index d9ea7b8096f..12b1d53d245 100644
--- a/packages/dev/core/src/ShadersWGSL/picking.vertex.fx
+++ b/packages/dev/core/src/ShadersWGSL/picking.vertex.fx
@@ -16,7 +16,7 @@ uniform viewProjection: mat4x4f;
 
 // Output
 #if defined(INSTANCES)
-varying vMeshID: f32;
+flat varying vMeshID: f32;
 #endif
 
 @vertex