Submitted by Lambda, also found by csanuragjain, Deivitto, R2, and Rolezn
https://github.com/code-423n4/2022-09-y2k-finance/blob/bca5080635370424a9fe21fe1aded98345d1f723/src/SemiFungibleVault.sol#L94
https://github.com/code-423n4/2022-09-y2k-finance/blob/bca5080635370424a9fe21fe1aded98345d1f723/src/Controller.sol#L168
https://github.com/code-423n4/2022-09-y2k-finance/blob/bca5080635370424a9fe21fe1aded98345d1f723/src/Controller.sol#L225
Certain tokens (e.g., STA or PAXG) charge a fee for transfers and others (e.g., USDT or USDC) may start doing so in the future. This is not correctly handled in multiple places and would lead to a loss of funds:
When fee-on-transfer tokens should be supported, you need to check the actual balance differences. If they are not supported, this should be clearly documented.
MiguelBits (Y2K Finance) acknowledged 
HickupHH3 (judge) commented:
