I've experienced a pretty game ruining bug with kerbalism's calculation of oxygen. The game is saying my crew has 34 days of life support at launch, but as the time warp increases towards minmus, it periodically lowers at every warp from 27 at the time to 23, 19, 11 and then 6 days. It's almost as if the way the scrubbers functioning is broken. (I checked before launch what the oxygen capacity was, and sure enough, it was just over 6 days) (80% efficiency btw)