There are many threads on this already, Tesla seems to think this is safer, many drivers disagree.
The theory seems to be that in the left lane, when you have a yellow line on your left, it hedges right to avoid the situation of a head on collision on an undivided road, whereas in other lanes it centres itself. Unfortunately people are finding that it is dangerously crowding traffic in the lane to the right instead.
This wasn't an issue on 7.0 and was introduced in 7.1 (ok, not technically true, in 7.0 the car tended to bias away from solid dividers and therefore towards moving vehicles, and people begged Tesla to fix this, Tesla made it worse instead of better)