vm.rollFork not working as expected in testTokenSupply function causing function to fail.

[unamewiki]

I'm using vm.rollFork feature in foundry to get _token.totalSupply() at two different blocks but test failing because its returning same totalSupply number for two different blocks. I have checked and totalSupply number, if tested individually for these two blocks returns different number.

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.21;

import {Test, console2} from "forge-std/Test.sol";

interface ERC20 {
    function totalSupply() external view returns (uint256);
}

contract rollForkTest is Test {
    uint256 mainnetFork;
    ERC20 _token;

    function setUp() public {
        vm.createSelectFork("https://rpc.ankr.com/eth");

        _token = ERC20(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2); //weth
    }

    function testTokenSupply() public {
        vm.rollFork(17958426);

        uint256 prev = _token.totalSupply();
        console2.log("totalSupply prev ", prev);
        console2.log("block", block.number, "timestamp", block.timestamp);

        vm.rollFork(18074858);

        uint256 later = _token.totalSupply();
        console2.log("totalSupply later", later);
        console2.log("block", block.number, "timestamp", block.timestamp);

        assertNotEq(prev, later);
    }

    function testTokenSupplyAtBlock_17958426() public {
        vm.rollFork(17958426);

        console2.log("totalSupply at block 17958426 :", _token.totalSupply());
        console2.log("block", block.number, "timestamp", block.timestamp);
    }

    function testTokenSupplyAtBlock_18074858() public {
        vm.rollFork(18074858);

        console2.log("totalSupply at block 18074858 :", _token.totalSupply());
        console2.log("block", block.number, "timestamp", block.timestamp);
    }
}