Submitted by ych18, also found by hickuphh3 and WatchPug
The CoreCollection.withdraw function uses payableToken.transferFrom(address(this), msg.sender, amount) to transfer tokens from the CoreCollection contract to the msg.sender ( who is the owner of the contract). The usage of transferFrom can result in serious issues. In fact, many ERC20 always require that in transferFrom allowance[from][msg.sender] >= amount, so in this case the call to the withdraw function will revert as the allowance[CoreCollection][CoreCollection] == 0 and therefore the funds cannot ben withdrawn and will be locked forever in the contract.
Replace transferFrom with transfer
sofianeOuafir (Joyn) confirmed and commented:
deluca-mike (judge) commented:
