Regarding the SOI trajectory accuracy thing - There was the warmly (not) accepted change to manuever planner, that is apparently result of rework to make the trajectory prediction more accurate based on TWR change during the burn.
So, since they are trying to improve/change that functionality, it may be counterproductive to fix a bug related to trajectory, just before(apart from) reworking the trajectory system. And yeah, it affects the trajectory even without manuever planned as far as I understand, but those two systems may be connected/ worked on simultaneously ... who knows.