Matching into a different Invasion mission type from the one I selected has been an ongoing "feature," but it hasn't been a problem until now. Apparently, I selected the Assassination mission on Neptune just as it moved from Neptune to Ceres, and ended up in a Sabotage mission instead. Unfortunately, I didn't think to abort, and wasted the token. Please consider having the Assassination mission stay put on one of the two Invasion planets to prevent this in the future. I know better now, others may not.