amount*accSlimePerShare.div(1e12) is greater than user.rewardDebt
This causes the contract calls to fail.pending = user.amount.mul(pool.accslimePerShare).div(1e12).sub(user.rewardDebt) ;
Users that withdraw a bigger amount vs the total will need wait more time to unstake the second time
When you attempt to unstake and high fees amount is showed on your transaction, that means this will fail due to the bug.