You cannot lose your Evers delegated to DePools.
However, some DePool validators specifics may create future risks of losing tokens.
Every DePool is linked to one of the Everscale blockchain validators. Validators generate new blocks of the network. The security of the blockchain depends on the quality of their work.
To improve the network stability, Surf plan to implement slashing in the future — a system of penalties for incorrect operation of the validator. So, if the validator didn't have time to sign the transaction, missed block generation or made other mistakes, it gets slashing points in the range from 0 to 1. When the score exceeds 0.66, a penalty amount will be deducted from the validator stake.
First of all, the penalty will be charged from the validator's funds — Validator assurance. But if the amount of the penalty exceeds the amount of the assurance, the remaining amount will be charged in equal shares from the stakes of all Depool depositors.
Although slashing is currently only being tested and does not affect validator stakes, slashing scores are very useful when selecting staking DePool.