I’m not sure if it’s exclusive to the A350 but the autopilot seems to change to the next way Waypoint quite early which causes the plane to suddenly change direction to try and Line up with the path of the next waypoint and when I try to switch back to there current waypoint I’m meant to be on, the system won’t let me as if I’ve already passed that point
I will admit the LNAV turning system in Infinite Flight isn’t that great - it does need an overhaul so it knows when to start the turn so as to line up with the next leg without (e.g.) overshooting it.
The distance varies depending on the direction change. The larger the turn needed, the earlier it “switches” to the next leg.