I have an odd issue. I am using several other mods, including KW Rocketry. I created a test rocket with my primary Lifter booster config and it launched without issue. When I took the lifter portion (Everything beyond the command module portion) and saved it, I tried to create a new rocket. Dropped in a command module and loaded my lifter and attached. For some reason any rocket created with this sub-assembly always ends up turning upside-down at about 1000-2000m. I had the same problem last night when I tried to do a different rocket, so I've been able to re-create this issue twice. In both cases, each time it launched fine prior to the sub-assembly and any future rockets flipped upside-down.