Why is delegatecall returning 0 and erroring?

Question

I'm working with OpenZeppelin upgradable proxies, as well as their governance. I have a propose function that looks like:

 function propose(
        address[] memory targets,
        uint256[] memory values,
        bytes[] memory calldatas,
        string memory description
    ) public virtual override returns (uint256) {
        uint256 proposalId = hashProposal(targets, values, calldatas, keccak256(bytes(description)));

        require(targets.length == values.length, "Governor: invalid proposal length");
        require(targets.length == calldatas.length, "Governor: invalid proposal length");
        require(targets.length > 0, "Governor: empty proposal");

        ProposalCore storage proposal = _proposals[proposalId];
        require(proposal.voteStart.isUnset(), "Governor: proposal already exists");

        uint64 snapshot = block.number.toUint64() + votingDelay().toUint64();
        uint64 deadline = snapshot + votingPeriod().toUint64();

        proposal.voteStart.setDeadline(snapshot);
        proposal.voteEnd.setDeadline(deadline);

        emit ProposalCreated(
            proposalId,
            _msgSender(),
            targets,
            values,
            new string[](targets.length),
            calldatas,
            snapshot,
            deadline,
            description
        );

        return proposalId;
    }

Which is the same as OpenZeppelin's GovernorUpgradeable contract.

Then, I'm calling the function from a proxy contract like so (in brownie):

tx = proxy_governor.propose(
        [vote_token_address],
        [0],
        [
            encode_function_data(
                vote_token.transfer, account.address, 1000000000000000000
            )
        ],
        "I want to pay myself 1 token. ",
        {"from": account},
    )

• vote_token_address is an ERC20 address.

• encode_function_data is a way to turn the function call into calldata. That part outputs: 0xa9059cbb00000000000000000000000066ab6d9362d4f35596279692f0251db6351658710000000000000000000000000000000000000000000000000de0b6b3a7640000, which should be the ABI encoded data for calling transfer on an ERC20, and sending 1 token to 0x643315C9Be056cDEA171F4e7b2222a4ddaB9F88D

I'm just trying to propose sending myself 1 token.

However, I'm running into this issue:

VirtualMachineError: Transaction reverted without a reason string: Transaction reverted without a reason string
Trace step 2517, program counter 862:
  File "/Users/patrick/.brownie/packages/OpenZeppelin/[email protected]/contracts/proxy/Proxy.sol", line 38, in Proxy._delegate:    
    case 0 {
        revert(0, returndatasize())
    }