Captain Ameria's shield got scratched by Black Panther in Captain America: Civil War. These were not scratches in the paint rather deep gauges made by Black Panther's vibranium claws. This being the case, why were these marks gone when Tony gave the shield back in Endgame?
If memory serves, Cap doesn't get his iconic shield back until Tony gives it back to him in Avengers: Engame. At this point around seven years have passed and we can assume that it's been repaired by most-likely Tony, or posibly the Wakandans.