Prevent tokens from getting stuck. This is a simple donation to every shareholder, and therefore, every share has more value (profit), leading to fewer shares for future users. If this is not intended by the user, it is merely a mistake! For totalAmountBefore > amount * totalShares, Here is the worst-case scenario (with the minimum amount): first deposit 0.001000 (e4) USDC → 1e12 shares. Second deposit: 0.001 (e4) USDC * 1e12 / 0.001 (e4) USDC. So, the attacker would need to donate 1e16 tokens, meaning 1e10 USDC → 10 billion $. Even in the worst case, it's informational.