If you took a hydrometer reading of the wort when it was 37F, then that would explain why it is high. It would adjust to 1.030 for a hydrometer that is calibrated at 60F. EDIT: Disregard, I double checked the math, it wouldn't be 1.030 Sounds like your FG ended a little bit high at 1.021 which would explain some of the sweetness, but it is a Bock after all. EDIT: Also, if its still lagering then that means its not fully carbed... The carbonation will give you a "dryer" sense too.