diff --git a/irr/include/ISkinnedMesh.h b/irr/include/ISkinnedMesh.h
index bb611bba2..869327bcd 100644
--- a/irr/include/ISkinnedMesh.h
+++ b/irr/include/ISkinnedMesh.h
@@ -159,15 +159,17 @@ class ISkinnedMesh : public IAnimatedMesh
 		core::array<SWeight> Weights;
 
 		//! Unnecessary for loaders, will be overwritten on finalize
-		core::matrix4 GlobalMatrix;
+		core::matrix4 GlobalMatrix; // loaders may still choose to set this (temporarily) to calculate absolute vertex data.
 		core::matrix4 GlobalAnimatedMatrix;
 		core::matrix4 LocalAnimatedMatrix;
+
+		//! These should be set by loaders.
 		core::vector3df Animatedposition;
 		core::vector3df Animatedscale;
 		core::quaternion Animatedrotation;
 
-		core::matrix4 GlobalInversedMatrix; // the x format pre-calculates this
-
+		// The .x and .gltf formats pre-calculate this
+		std::optional<core::matrix4> GlobalInversedMatrix;
 	private:
 		//! Internal members used by CSkinnedMesh
 		friend class CSkinnedMesh;
diff --git a/irr/src/CB3DMeshFileLoader.cpp b/irr/src/CB3DMeshFileLoader.cpp
index 66ad64a6f..edce3f1d8 100644
--- a/irr/src/CB3DMeshFileLoader.cpp
+++ b/irr/src/CB3DMeshFileLoader.cpp
@@ -389,6 +389,7 @@ bool CB3DMeshFileLoader::readChunkVRTS(CSkinnedMesh::SJoint *inJoint)
 		// Transform the Vertex position by nested node...
 		inJoint->GlobalMatrix.transformVect(Vertex.Pos);
 		inJoint->GlobalMatrix.rotateAndScaleVect(Vertex.Normal);
+		Vertex.Normal.normalize(); // renormalize: normal might have been skewed by scaling
 
 		// Add it...
 		BaseVertices.push_back(Vertex);
diff --git a/irr/src/CSkinnedMesh.cpp b/irr/src/CSkinnedMesh.cpp
index 5e1452601..9e2e399da 100644
--- a/irr/src/CSkinnedMesh.cpp
+++ b/irr/src/CSkinnedMesh.cpp
@@ -222,6 +222,7 @@ void CSkinnedMesh::buildAllLocalAnimatedMatrices()
 
 			// IRR_TEST_BROKEN_QUATERNION_USE: TODO - switched to getMatrix_transposed instead of getMatrix for downward compatibility.
 			//								   Not tested so far if this was correct or wrong before quaternion fix!
+			// Note that using getMatrix_transposed inverts the rotation.
 			joint->Animatedrotation.getMatrix_transposed(joint->LocalAnimatedMatrix);
 
 			// --- joint->LocalAnimatedMatrix *= joint->Animatedrotation.getMatrix() ---
@@ -496,8 +497,7 @@ void CSkinnedMesh::skinJoint(SJoint *joint, SJoint *parentJoint)
 {
 	if (joint->Weights.size()) {
 		// Find this joints pull on vertices...
-		core::matrix4 jointVertexPull(core::matrix4::EM4CONST_NOTHING);
-		jointVertexPull.setbyproduct(joint->GlobalAnimatedMatrix, joint->GlobalInversedMatrix);
+		core::matrix4 jointVertexPull = joint->GlobalAnimatedMatrix * joint->GlobalInversedMatrix.value();
 
 		core::vector3df thisVertexMove, thisNormalMove;
 
@@ -510,8 +510,10 @@ void CSkinnedMesh::skinJoint(SJoint *joint, SJoint *parentJoint)
 			// Pull this vertex...
 			jointVertexPull.transformVect(thisVertexMove, weight.StaticPos);
 
-			if (AnimateNormals)
+			if (AnimateNormals) {
 				jointVertexPull.rotateAndScaleVect(thisNormalMove = weight.StaticNormal);
+				thisNormalMove.normalize(); // must renormalize after potentially scaling
+			}
 
 			if (!(*(weight.Moved))) {
 				*(weight.Moved) = true;
@@ -755,9 +757,9 @@ void CSkinnedMesh::calculateGlobalMatrices(SJoint *joint, SJoint *parentJoint)
 	joint->LocalAnimatedMatrix = joint->LocalMatrix;
 	joint->GlobalAnimatedMatrix = joint->GlobalMatrix;
 
-	if (joint->GlobalInversedMatrix.isIdentity()) { // might be pre calculated
+	if (joint->GlobalInversedMatrix.has_value()) { // might be pre calculated
 		joint->GlobalInversedMatrix = joint->GlobalMatrix;
-		joint->GlobalInversedMatrix.makeInverse(); // slow
+		joint->GlobalInversedMatrix->makeInverse(); // slow
 	}
 
 	for (u32 j = 0; j < joint->Children.size(); ++j)
diff --git a/irr/src/CXMeshFileLoader.cpp b/irr/src/CXMeshFileLoader.cpp
index 5978980f4..c32f01299 100644
--- a/irr/src/CXMeshFileLoader.cpp
+++ b/irr/src/CXMeshFileLoader.cpp
@@ -994,9 +994,9 @@ bool CXMeshFileLoader::parseDataObjectSkinWeights(SXMesh &mesh)
 	// transforms the mesh vertices to the space of the bone
 	// When concatenated to the bone's transform, this provides the
 	// world space coordinates of the mesh as affected by the bone
-	core::matrix4 &MatrixOffset = joint->GlobalInversedMatrix;
-
+	core::matrix4 MatrixOffset;
 	readMatrix(MatrixOffset);
+	joint->GlobalInversedMatrix = MatrixOffset;
 
 	if (!checkForOneFollowingSemicolons()) {
 		os::Printer::log("No finishing semicolon in Skin Weights found in x file", ELL_WARNING);