Submitted by adriro
https://github.com/code-423n4/2023-12-particle/blob/a3af40839b24aa13f5764d4f84933dbfa8bc8134/contracts/protocol/ParticlePositionManager.sol#L424 
https://github.com/code-423n4/2023-12-particle/blob/a3af40839b24aa13f5764d4f84933dbfa8bc8134/contracts/protocol/ParticlePositionManager.sol#L432
When a position is closed, there is no check to ensure that the effective added liquidity covers the original borrowed liquidity from the LP.
Closing a position in the Particle LAMM protocol must ensure that the borrowed liquidity gets fully added back to the LP. Independently of the outcome of the trade, the LP should get its liquidity back. The implementation of _closePosition() calculates the required amounts and executes a call to LiquidityPosition.increaseLiquidity(), which ends up calling increaseLiquidity() in the Uniswap Position Manager.
https://github.com/code-423n4/2023-12-particle/blob/a3af40839b24aa13f5764d4f84933dbfa8bc8134/contracts/protocol/ParticlePositionManager.sol#L422-L439
As we can see in lines 424 and 432, the effective results of the liquidity increment are returned from the call to Uniswap NPM. Both amountToAdd and amountFromAdd are correctly overwritten with the actual amounts used by the addLiquidity() action, but liquidityAdded is simply assigned to the cache and never checked.
The effective added liquidity may fall short to cover the original borrowed liquidity, and if so the lien will be closed without returning the full amount to the LP.
Ensure the effective added liquidity covers the original borrowed amount.
wukong-particle (Particle) acknowledged and commented:
