Users need to lock in WAVES in Neutrino's smart contracts to mint USDN, while USDN redemptions have the opposite effect of destroying the stablecoin to unlock WAVES supply.
According to data source Defi Llama, the total value locked in the DeFi platform [vires.finance] has dropped to $945 million from a record $1.26 billion in three days.
And on CoinDesk:
Waves' USDN Stablecoin Loses Peg, Drops 15% Amid Manipulation Scare https://www.coindesk.com/markets/2022/04/04/waves-usdn-stablecoin-loses-peg-drops-15-amid-manipulation-scare https://archive.ph/ckmNW <-- An archive, which may be easier to read.