Riot made a sticky saying it was alot of effort to take away skins and gemstomes from people who got hundreds of chests for free. But Garena who runs certain regions of League of Legends was able to. At this post here. Vietname is also the second largest region according to riot. https://lienminh.garena.vn/thongbao/loi-hop-huyet-nguyet-mo-ban-bang-tinh-hoa-lam they state.
"On the morning of January 11, 2019, while adding items to the store for patch 9.1, there was an incident that caused the Blood Moon Capsules to be sold for 1 BE, while the actual value of this item is 140 RP. The price was up for about 20 minutes, during which, some players bought the Blood Moon Capsules with BE.
To ensure fairness, the technician team reverted all the Blood Moon Capsules purchased with BE, including skins, related skins, gemstones, and (I'm not sure what "crystal fragments" are. Skin shards maybe?) were removed from accounts.
In the future, some measures will be implemented to prevent similar incidents from happening.