launch stability enhancer following my craft to orbit

[Cerber]

OS: windows 7 sp1 64 bits

no mods installed, all stock parts

i made a craft which uses 4 TT18-A Launch Stability Enhancers, and every time i use it one of them ends up in orbit

it doesn't happen with my other crafts that use the TT18-A, and there is always only 1 being pulled to orbit

during the ascent, on the map i see a debris following my ship and changing trajectory as my ship does but when looking at the ship i see no debris

once i reach orbit, that debris seems to detach from the ship and stays in stable orbit (though when i fly it later, it goes out of physics engine and flies in a straight line rather than circular orbit)

screenshot of the bug:

craft file:

https://dl.dropboxusercontent.com/u/36319416/rescue%20ship.craft

on the plus side, it looks pretty funny!