The position can be exercised if current block timestamp is less than the positions expiration.
The position can be withdrawed if current block timestamp is greater than the positions expiration
However, when current block timestamp is equal to the positions expiration (block.timestamp == positionExpirations), the state is unknown (cannot be exercised or withdraw)
https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L401
https://github.com/code-423n4/2022-06-putty/blob/3b6b844bc39e897bd0bbb69897f2deff12dc3893/contracts/src/PuttyV2.sol#L481
Allow the user to withdraw the position upon expiration.
