Havent read the whole thread but if it has not been posted yet this is likely what happened.
you had a buddy at some point in a free aim session and you joined his game it quickly notified you that the aiming would be changed but you didnt pay attention and you joined it. maybe it was even just for a race so aiming doesnt even matter. but since it switched over to free aim it locked it in also in single player. so when it saves everytime you will be back in free aim when you join unless you go back to single player and change it back to auto aim or join a friends session that is in auto aim.
that said you are that high level and dont want to take the time to use free aim you are just cheating yourself from a more satisfying gaming experience.
the same people who bash on money glitchers for "ruining their own fun" are often the same people who play on auto aim and its really the same thing. you ruin your own fun by resorting to letting the ai aim for you. trust me when you finish a hard mission solo in free aim its 10x more gratifying then finishing it on auto aim. its the same with buying that entity after legitly grinding the money vs glitching for it.