Why NASCAR penalized Bubba Wallace after Atlanta race finish

Bubba Wallace went from a top-three finish to the tail end of the lead lap on July 13 at the NASCAR Atlanta race.Wallace was penalized postrace of the Quaker State 400. Wallace was running third on the last lap behind Ryan Blaney and Carson Hocevar when he zoomed to the inside of Hocevar but went below the yellow line. He came back above the line and was three wide with Hocevar and Ryan Blaney. Wallace finished second in real time before he was penalized by NASCAR for advancing his position by g