The use of payable.transfer() is heavily frowned upon because it can lead to the locking of funds. The transfer() call requires that the recipient has a payable callback, only provides 2300 gas for its operation. This means the following cases can cause the transfer to fail:
uses the onlyVault modifier, and vaults currently have empty payable callbacks, so they dont currently revert
https://github.com/code-423n4/2022-04-backd/blob/c856714a50437cb33240a5964b63687c9876275b/backd/contracts/vault/VaultReserve.sol#L81
uses the onlyPoolOrGovernance modifier, and pools currently have an empty payable callback, so they dont currently rever. Governance is currently deployed and not seeing issues, so presumably it also has an empty payable callback
https://github.com/code-423n4/2022-04-backd/blob/c856714a50437cb33240a5964b63687c9876275b/backd/contracts/vault/EthVault.sol#L29
the treasury is currently deployed and not seeing issues, so presumably it also has an empty payable callback
https://github.com/code-423n4/2022-04-backd/blob/c856714a50437cb33240a5964b63687c9876275b/backd/contracts/vault/EthVault.sol#L37
vaults currently have an empty payable callback
https://github.com/code-423n4/2022-04-backd/blob/c856714a50437cb33240a5964b63687c9876275b/backd/contracts/strategies/BkdEthCvx.sol#L77
vaults currently have an empty payable callback
https://github.com/code-423n4/2022-04-backd/blob/c856714a50437cb33240a5964b63687c9876275b/backd/contracts/strategies/BkdEthCvx.sol#L93
vaults currently have an empty payable callback
https://github.com/code-423n4/2022-04-backd/blob/c856714a50437cb33240a5964b63687c9876275b/backd/contracts/strategies/BkdEthCvx.sol#L117
