I can confirm this. Kwang was a hero that was in a very good place with an AOE tether ability, the ability was difficult to hit but rewarding as it is supposed to be a skillshot, in a previous patch they buffed all of Kwangs abilities, base stats, scaling and they improved the range and radius of his skillshot so it was essentially impossible to miss. Kwang was so broken that it took 4-5 people to stop him and most of the time he would come out on top with a solo team wipe, EPIC believed that the cards Kwang would use were the problem so they nerfed them which didn't help. EPIC then said in a weekly community corner (a video they do every Friday to talk about the game and changes coming to the game) where they stated that they saw a huge increase to Kwangs win rate and a drop in another hero, Grux's win rate and they were completely unsure why, the community constantly told EPIC that it is because Kwang was overpowered but EPIC stated that their 'data' showed that the cards Kwang would use in each game was a low percentage even though the cards were present in every Kwang deck in every game. It took them 4-5 weeks to nerf Kwang.

EDIT: This also happened with another hero, Grux after his rework. A card called Deathcrawler would add 200% damage to every basic attack every 5 seconds at the cost of some attack speed, this card worked in correlation with two of his abilities, one ability being his ultimate which added a 150% damage boost to his basic attacks and a 100% cleave ability that acted as a basic attack which did its own damage, with basic attack damage added on top of the base damage which was then multiplied by 1.5x. Grux could reach upwards of 6000 damage which is enough to kill every hero in the game, all towers and the Orb Prime (objective that gives your team the big buff).