Strange gas fee behavior

[jbastruz]

Hi guys,

I just realized something unexpected, and I would like to share it with you.
(Notice that I code my NFT on the avalanche blockchain) When I mint my NFT, the gas fee can be 15x more than expected, according to a amount of AVAX I send... here is my code:

contract Nft is ERC721Royalty, ERC721Enumerable, Ownable, PaymentSplitter {

    using SafeMath for uint256;

    uint256 private s_tokenCounter;
    address[] private s_team = [0x[...], msg.sender];
    uint256[] private s_SharesTeam = [50, 50];
    bool public paused = false;

    mapping(uint256 => uint256) private s_nbOwners;

    constructor(
        string memory CollectionName,
        string memory Sigle,
        uint96 _royaltyFeesInBips
    ) payable ERC721(CollectionName, Sigle) PaymentSplitter(s_team, s_SharesTeam) {
        s_tokenCounter = 0;
        setRoyaltyInfo(msg.sender, _royaltyFeesInBips);
    }

    function mintNft() external payable {
        require(!paused, "The mint's not available for now, be patient ;)");
        require(msg.value >= 4, "Not enough avax");

        s_tokenCounter = s_tokenCounter + 1;
        _safeMint(msg.sender, s_tokenCounter);
        s_nbOwners[s_tokenCounter] = 1;
    }

    [...]
}

When I send 4 AVAX, the gas fee is about 0.005 AVAX :

When i send not enough money, the gas fee is about 0.08 AVAX :

It seems the a revert cost quite a lot, so you should have it in mind !