diff --git a/src/BulletCollision/CollisionShapes/btCompoundShape.cpp b/src/BulletCollision/CollisionShapes/btCompoundShape.cpp
index a65f949c8..36906a75f 100644
--- a/src/BulletCollision/CollisionShapes/btCompoundShape.cpp
+++ b/src/BulletCollision/CollisionShapes/btCompoundShape.cpp
@@ -306,7 +306,7 @@ const char*	btCompoundShape::serialize(void* dataBuffer, btSerializer* serialize
 			memPtr->m_childMargin = float(m_children[i].m_childMargin);
 			memPtr->m_childShape = (btCollisionShapeData*)serializer->getUniquePointer(m_children[i].m_childShape);
 			//don't serialize shapes that already have been serialized
-			if (!serializer->findPointer(memPtr->m_childShape))
+			if (!serializer->findPointer(m_children[i].m_childShape))
 			{
 				btChunk* chunk = serializer->allocate(m_children[i].m_childShape->calculateSerializeBufferSize(),1);
 				const char* structType = m_children[i].m_childShape->serialize(chunk->m_oldPtr,serializer);
diff --git a/src/BulletCollision/NarrowPhaseCollision/btSubSimplexConvexCast.cpp b/src/BulletCollision/NarrowPhaseCollision/btSubSimplexConvexCast.cpp
index 4c709a8c3..18eb662de 100644
--- a/src/BulletCollision/NarrowPhaseCollision/btSubSimplexConvexCast.cpp
+++ b/src/BulletCollision/NarrowPhaseCollision/btSubSimplexConvexCast.cpp
@@ -114,7 +114,10 @@ bool	btSubsimplexConvexCast::calcTimeOfImpact(
 				hasResult = true;
 			}
 		} 
-		m_simplexSolver->addVertex( w, supVertexA , supVertexB);
+		///Just like regular GJK only add the vertex if it isn't already (close) to current vertex, it would lead to divisions by zero and NaN etc.
+		if (!m_simplexSolver->inSimplex(w))
+			m_simplexSolver->addVertex( w, supVertexA , supVertexB);
+
 		if (m_simplexSolver->closest(v))
 		{
 			dist2 = v.length2();