I faced this bug several times before but this is my first time reporting it.
This is nothing with the new experimental beta or the mods used I guess, since last time I got this bug was a year ago.
I presume this happens because the game doesn't update CoL if some parts are removed or a stage has been activated.
*The more accurate description:
Because of Aerodynamics, a typical looking reentry capsule faces heatshield forward in atmosphere. This is neat for reentry, but not good for Dragon style launch abort system. To compensate this, Apollo and Orion has Launch Escape Tower to put CoT in front of CoL and CoD. In Dragon's case, it aborts with trunk to put CoL and CoD behind of CoT.
My capsule used Dragon's method. So technically it shouldn't be able to abort properly without its aeroshell. It didn't earlier today, as law of Aerodynamics said. However, all of a sudden, it starts to ascend directly upward as if Aerodynamics is not in calculation. I assume this is a bug.
@AndrewGarrison Oh, seems like I confused something while writing this - the tumbling comes from CoM and CoT placement, so not related to aerodynamic force. What related to the aerodynamic force is, if you put an aeroshell or a trunk of Dragon V2, it stops tumbling. See the videos