// In Position.sol - the validation that was failing:
if (liquidityDelta == 0) {
    if (liquidity == 0) CannotUpdateEmptyPosition.selector.revertWith(); // ← This error
}

    function test_fuzz_update(
        int128 liquidityDelta,
        Position.State memory pos,
        uint256 newFeeGrowthInside0X128,
        uint256 newFeeGrowthInside1X128
    ) public {
        Position.State storage position = positions[0];
        position.liquidity = pos.liquidity;
        position.feeGrowthInside0LastX128 = pos.feeGrowthInside0LastX128;
        position.feeGrowthInside1LastX128 = pos.feeGrowthInside1LastX128;

        uint128 oldLiquidity = position.liquidity;

        if (position.liquidity == 0 && liquidityDelta == 0) {
            vm.expectRevert(Position.CannotUpdateEmptyPosition.selector);
        }
}

// Skip positions that have no liquidity to avoid CannotUpdateEmptyPosition error  
if (liquidity == 0) {
    burnedPositions[i] = BurnedPosition({
        tickLower: positions[i].tickLower,
        tickUpper: positions[i].tickUpper, 
        amount0Received: 0,
        amount1Received: 0
    });
    continue; // Skip the modifyLiquidity call
}