Invariants to the VotingEscrow contract can be broken.  While an enormous quantity is necessary, greater than the total supply of $CANTO, its worth mentioning due to the fact that invariants in the system can be broken, if only in testing environments.
Invariants affected in VotingEscrow.sol:
Cases in VotingEscrow.sol where casting creates vulnerable attack surfaces:
https://github.com/code-423n4/2023-08-verwa/blob/a693b4db05b9e202816346a6f9cada94f28a2698/src/VotingEscrow.sol#L317 
https://github.com/code-423n4/2023-08-verwa/blob/a693b4db05b9e202816346a6f9cada94f28a2698/src/VotingEscrow.sol#L305
https://github.com/code-423n4/2023-08-verwa/blob/a693b4db05b9e202816346a6f9cada94f28a2698/src/VotingEscrow.sol#L276
https://github.com/code-423n4/2023-08-verwa/blob/a693b4db05b9e202816346a6f9cada94f28a2698/src/VotingEscrow.sol#L278
https://github.com/code-423n4/2023-08-verwa/blob/a693b4db05b9e202816346a6f9cada94f28a2698/src/VotingEscrow.sol#L300
https://github.com/code-423n4/2023-08-verwa/blob/a693b4db05b9e202816346a6f9cada94f28a2698/src/VotingEscrow.sol#L317
Debugging and auditing this code is made more complex due to the inclusion of this casting, which puts the protocol more at risk than had they been unused.
Its not fully clear why the types for amount and delegated  of the LockedBalance struct are of type int128.  This could introduce unforseen edge cases due to the copious casting.  All assignments from function arguments are of type uint256 (coming from createLock() and increaseAmount()), making the usage more peculiar and inconsistent. Similarly, int128 is used for bias and slope of the Point struct, and in all places where they are used for calculations, they must be checked for being negative and are subsequently reset to 0 in the case of being negative. The suspicion is that since the origin of the ve system came from the original Curve contracts, the implicit assumptions of that system were kept wholesale.
Use unsigned integers for all financial calculations so that all casting is removed and remove the subsequent unnecessary resets to 0. Instead, for places where the resets are used, define pre-conditions  that ensure negative-valued outcomes are not permissible in calls to createLock() and increaseLock().
