Random Number Generation Issue Post Titan Upgrade

[kaijudev]

Describe the bug
I'm seeing an issue after the Titan upgrade where contracts that use random number generation in solidity are not working. The transaction gets submitted but never gets picked up by the blockchain or indexed. The cro value and gas seem to be taken out of the account though. I can't provide a tx hash since it is never indexed. This issue seems isolated to using a random number generation function in a contract from what I can tell. Potentially one of the properties off block?

Here is an example of a random number generation function that causes the issue:

function getRandomAvailableTokenId(address to, uint updatedNumAvailableTokens)
        internal
        returns (uint256)
    {
        uint256 randomNum = uint256(
            keccak256(
                abi.encode(
                    to,
                    tx.gasprice,
                    block.number,
                    block.timestamp,
                    block.difficulty,
                    blockhash(block.number - 1),
                    address(this),
                    updatedNumAvailableTokens
                )
            )
        );
        uint256 randomIndex = (randomNum % updatedNumAvailableTokens) + 1;
        return getAvailableTokenAtIndex(randomIndex, updatedNumAvailableTokens + 1);
    }```


**Expected behavior**

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[yihuang]

yes, it's known to us and we are trying to fix the network ASAP.