Then things began going downhill. Ning was taken out of the national swimming team for participating in private commercial activities and over disputes with the team, and was sent back to his original Chinese Navy team for training in 2017.

Later that year, Ning broke his previous national record to surge to victory in the 100m freestyle at the short course swimming race in Queensland, Australia, finishing in 46.64 seconds. Ning also won the men's 50m freestyle gold medal in 21.77 seconds in Queensland.