Mantis#1990. Thank you kindly, Nlin and M.Igarashi for a patch that:

This patch improves LSL conformance by inserting a 0.2 second delay 
into llSetPos/llSetRot, as the function specification states. 
Thanks to M. Igarashi for the patch.

OpenSim/Region/ScriptEngine/Common/LSL_BuiltIn_Commands.cs

@@ -1510,6 +1510,9 @@ namespace OpenSim.Region.ScriptEngine.Common
             m_host.AddScriptLPS(1);
 
             SetPos(m_host, pos);
+
+            // sleep for 0.2 seconds
+            System.Threading.Thread.Sleep(200);
         }
 
         private void SetPos(SceneObjectPart part, LSL_Types.Vector3 pos)
@@ -1554,6 +1557,9 @@ namespace OpenSim.Region.ScriptEngine.Common
             m_host.AddScriptLPS(1);
 
             SetRot(m_host, rot);
+
+            // sleep for 0.2 seconds
+            System.Threading.Thread.Sleep(200);
         }
 
         private void SetRot(SceneObjectPart part, LSL_Types.Quaternion rot)