diff --git a/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs b/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
index 465d76db3f..ddbd677e3e 100644
--- a/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
+++ b/OpenSim/Region/ClientStack/Linden/UDP/LLClientView.cs
@@ -6601,8 +6601,18 @@ namespace OpenSim.Region.ClientStack.LindenUDP
 
                 AgentRequestSit handlerAgentRequestSit = OnAgentRequestSit;
                 if (handlerAgentRequestSit != null)
-                    handlerAgentRequestSit(this, agentRequestSit.AgentData.AgentID,
-                                           agentRequestSit.TargetObject.TargetID, agentRequestSit.TargetObject.Offset);
+                    if (!(agentRequestSit.AgentData == null
+                        || agentRequestSit.TargetObject == null
+                        || agentRequestSit.TargetObject.TargetID == null
+                        || agentRequestSit.TargetObject.Offset == null))
+                    {
+                        var sp = m_scene.GetScenePresence(agentRequestSit.AgentData.AgentID);
+                        if (sp == null || sp.ParentID != 0) // ignore packet if agent is already sitting
+                            return true;
+
+                        handlerAgentRequestSit(this, agentRequestSit.AgentData.AgentID,
+                                               agentRequestSit.TargetObject.TargetID, agentRequestSit.TargetObject.Offset);
+                    }
             }
             return true;
         }
diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
index 400d5d6b2e..8fd054f754 100644
--- a/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSPrim.cs
@@ -169,6 +169,7 @@ public sealed class BSPrim : BSPhysObject
     public override PrimitiveBaseShape Shape {
         set {
             BaseShape = value;
+            LastAssetBuildFailed = false;
             ForceBodyShapeRebuild(false);
         }
     }
@@ -178,7 +179,6 @@ public sealed class BSPrim : BSPhysObject
 
     public override bool ForceBodyShapeRebuild(bool inTaintTime)
     {
-        LastAssetBuildFailed = false;
         PhysicsScene.TaintedObject(inTaintTime, "BSPrim.ForceBodyShapeRebuild", delegate()
         {
             _mass = CalculateMass();   // changing the shape changes the mass