Vyper bool doesn't match the SolidityProxy bool variable

I'm not sure whether it's a bug or my lack of experience with Vyper

What's your issue about?

(min reproducible code I could make)

I have very simple Vyper contract

a: public(address)
b: public(bool)
c: public(uint256)

@external
def __init__(_a: address):
    self.a = _a
    self.c = block.timestamp + 2

@external
def set_b_true():
    self.b = True

and Solidity delegator with OZ proxy full code

contract SolidityProxy {
    address public a;
    bool public b;
    uint256 public c;

    constructor(address _a) public {
        a = _a;
        c = block.timestamp + 2;
    }
 // The proxy code is from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/proxy/Proxy.sol
...

now, if you call set_b_true via Proxy - your c variable would 1, but b won't be affected. You might think the the proxy code is wrong, but I tried two different impl and both worked with everything except bool variable, including arrays (but array with constant size in Vyper somehow only work with array with dynamic size in Solidity proxy so I assume it's my lack of understanding of laguages?)

const VyperContract = artifacts.require('VyperContract');
const SolidityProxy = artifacts.require('SolidityProxy');

contract('test', (accounts) => {

    beforeEach(async () => {
        const [a] =  accounts;
        this.vyperContract = await VyperContract.new(a);
        this.solidityProxy = await SolidityProxy.new(a, this.vyperContract.address);
        this.solidityProxy = await VyperContract.at(this.solidityProxy.address);
    });

    const getState = async (myContract) =>  {
        const a = ((await myContract.a()).toString());
        const b = ((await myContract.b()).toString());
        const c = ((await myContract.c()).toString());
        return {a, b, c};
    }

    it("compareStates", async() => {
        // since it's the contracts the same - you would expect the variables are the same as well
        console.log(await getState(this.vyperContract));
        // {
        //     a: '0xA51043a9afD5e8Fd2869b2cb6d83b568650CB4A4',
        //     b: 'false',
        //     c: '1609608804'
        // }
        console.log(await getState(this.solidityProxy));
        // {
        //     a: '0xA51043a9afD5e8Fd2869b2cb6d83b568650CB4A4',
        //     b: 'false',
        //     c: '1609608805'
        // }

        await this.solidityProxy.set_b_true();
        console.log(await getState(this.solidityProxy));
        // { a: '0xA51043a9afD5e8Fd2869b2cb6d83b568650CB4A4', b: 'false', c: '1' }
        // different result is expected!!!
    });
});

Version Information

vyper Version (output of vyper --version): x.x.x vyper: 0.2.8+commit.069936f solc: 0.6.12+commit.27d51765.Emscripten.clang
OS: osx/linux/win macOS 10.13.6 MacBook Pro (Retina, 13-inch, Late 2012)
Python Version (output of python --version): Python 3.9.1
Environment (output of pip freeze): apipkg==1.5 appdirs==1.4.4 asttokens==2.0.4 attrs==20.2.0 base58==2.0.1 bitarray==1.2.2 black==19.10b0 certifi==2020.6.20 chardet==3.0.4 click==7.1.2 cytoolz==0.11.0 eth-abi==2.1.1 eth-account==0.5.2 eth-brownie==1.11.10 eth-event==1.2.0 eth-hash==0.2.0 eth-keyfile==0.5.1 eth-keys==0.3.3 eth-rlp==0.2.1 eth-typing==2.2.2 eth-utils==1.9.5 execnet==1.7.1 hexbytes==0.2.1 hypothesis==5.35.0 idna==2.10 inflection==0.5.0 iniconfig==1.1.1 ipfshttpclient==0.6.1 jsonschema==3.2.0 lru-dict==1.1.6 more-itertools==8.5.0 multiaddr==0.0.9 mythx-models==1.9.1 netaddr==0.8.0 packaging==20.4 parsimonious==0.8.1 pathspec==0.8.0 pluggy==0.13.1 prompt-toolkit==3.0.7 protobuf==3.13.0 psutil==5.7.3 py==1.9.0 py-solc-ast==1.2.5 py-solc-x==1.0.0 pycryptodome==3.9.8 Pygments==2.6.1 pygments-lexer-solidity==0.5.1 PyJWT==1.7.1 pyparsing==2.4.7 pyrsistent==0.17.3 pytest==6.0.1 pytest-forked==1.3.0 pytest-xdist==1.34.0 python-dateutil==2.8.1 python-dotenv==0.15.0 pythx==1.6.1 PyYAML==5.3.1 regex==2020.10.28 requests==2.24.0 rlp==1.2.0 semantic-version==2.8.5 six==1.15.0 sortedcontainers==2.2.2 toml==0.10.1 toolz==0.11.1 tqdm==4.48.2 typed-ast==1.4.1 urllib3==1.25.11 varint==1.0.2 vvm==0.1.0 vyper==0.2.8 wcwidth==0.2.5 web3==5.11.1 websockets==8.1

How can it be fixed?

I think the example of working proxy would be great? I don't know

vyperlang / vyper