False positive on SUICIDE instruction check

Version: 0.10.13

I’ve tried to parse down a contract to the most minimal working example of a (potential) false positive. In the code below, I’m not sure how the function setFlag can modify the address owner, but myth seems to think I can:

pragma solidity ^0.4.2;

contract TOY  {

    address public owner;
    bool public FLAG;

    modifier checkOwner {
        require(msg.sender == owner);  _;
    }

    function TOY() { owner = msg.sender; }
    function setFlag(bool newFLAG) public { FLAG = newFLAG;  }
    function boom() public checkOwner {
        selfdestruct(owner);
    }
}

When running myth -x TOY.sol I get the output

==== Unchecked SUICIDE ====
Type: Warning
Contract: TOY
Function name: boom()
PC address: 505
The function boom() executes the SUICIDE instruction.
The remaining Ether is sent to a stored address

There is a check on storage index 6. This storage index can be written to by calling the function 'setFlag(bool)'.

[JoranHonig]

Works correctly in master, closing

[thoppe]

Version: mythril==0.13.15

Another example, this time of contract code in the wild. 0x0dc568fc30eb731b6551848382e53bdf2c47a230

Type: Warning
Contract: CryptoBetOn
Function name: killContract()
PC address: 1416
The function killContract() executes the SUICIDE instruction. The remaining Ether is sent to a stored address.
There is a check on storage index 6. This storage index can be written to by calling the function 'acceptBet(uint256,uint8)'.

A glance at the linked source show no modification of owner using acceptBet.