Submitted by 0x52, also found by Bahurum, Jeiwan, Lambda, PwnPatrol, and thebensams
https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/Vault.sol#L244-L252
https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/SemiFungibleVault.sol#L205-L213
https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/SemiFungibleVault.sol#L237-L239
https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/SemiFungibleVault.sol#L244-L246
https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/SemiFungibleVault.sol#L251-L258
https://github.com/code-423n4/2022-09-y2k-finance/blob/ac3e86f07bc2f1f51148d2265cc897e8b494adf7/src/SemiFungibleVault.sol#L263-L270
Other protocols that integrate with Y2K may wrongly assume that the functions are EIP-4626 compliant. Thus, it might cause integration problems in the future that can lead to wide range of issues for both parties.
All official EIP-4626 requirements can be found on its official page. Non-compliant functions are listed below along with the reason they are not compliant:
The following functions are missing but should be present:
The following functions are non-compliant because they dont account for withdraw and deposit locking:
All of the above functions should return 0 when their respective functions are disabled (i.e. maxDeposit should return 0 when deposits are disabled)
previewDeposit is not compliant because it must account for fees which it does not
totalAssets is not compliant because it does not always return the underlying managed by the vault because it fails to include the assets paid out during a depeg or the end of the epoch.
All functions listed above should be modified to meet the specifications of EIP-4626.
MiguelBits (Y2K Finance) confirmed 
HickupHH3 (judge) commented:
