This might be a bit worrying my mate got a reply from lrp have a look
http://www.lrp.cc/forum/viewtopic.php?f=13&t=8280
we were chatting about this yesterday we reckon It might be a problem with big torque servos he runs a vortex 14kg one. when he gets his new sxx he is going to try a low profile servo instead to see if it clears the problem