Yeah I was getting that to, And Mine suddenly started a extremely erratic spin out side of the atmosphere. I never managed to actually recover it not for lack of trying.
After A While though I got bored and took the engine off the Farscape module and used it in place of the default ones. I got it to take off like a SSTO. It made orbit then it went out of control. However, Because the engine on the farscape are ridiculously OP vs the fuel consumption and the fact I was using two of them on a craft that had a larger Fuel and Oxidizer load, It had enough delta V that had it not gone crazy, It would easily have reached escape orbit with plenty of go juice.