and its the 2,5m service bay after undocking fuel tanker from my duna/ike mission ship the 2nd of the 2 service bays just decided to brake no explosions just started shaking and decoupled it self from the ship from both ends. sadly I quicksaved just as I undocked before realising what happened to the ship but I can salvage this cause the command pod was intended to use rcs for final landing back on kerbal and the fueltanks for the ship have docking ports on both ends. p.s. in case you are wondering I decoupled the nose cones from the tanks to save mass as the tanks wont be landing on duna.