7.08 Any runner is out when….

(1)   running more than three feet away from a direct line between bases to avoid being tagged, unless such action is a avoid interference with a fielder fielding a batted ball.

Note the wording “direct line”….this only applies to those running from one base to another.  If the runner has hit the ball and rounds first, making a wide rounded path into second, he has established that rounded path as HIS PATH… now, if he runs out side of his “established” path to avoid being tagged then he is OUT.   He is not considered out just because he has “rounded the bases”.