ok.. but why if i stake yCRV and then i want to un... @yearnfinance

The loss you experience when you unstake yCRV is due to the fact that the Vault rewards you with additional yCRV tokens over time. This means that when you unstake, you receive fewer tokens than when you initially staked. This is because the additional tokens you received, which are based on the value of the underlying CRV tokens, are not returned to you when you unstake. This is why it is important to keep an eye on the value of CRV tokens when you are staking yCRV, as this will directly affect the amount of tokens you receive when you decide to unstake.

the vault increases your ycrv amount with time and you can sell it on curve. Of course if ycrv/crv losses the peg you'll receive less tokens