UserReserve scaledATokenBalance are wrong ?

For the convenience of locating the data, I directly queried userReserves by id

{
  userReserves(where: {
      id: "0xe813e410f1841c06e40bff0407f7f4b63bc3ff360x7ceb23fd6bc0add59e62ac25578270cff1b9f6190xd05e3e715d945b59290df0ae8ef85c1bdb684744"
    }) {
      id
      reserve {
        symbol,
        underlyingAsset
      },
      user {
        id
      }
      currentATokenBalance,
      currentStableDebt,
      scaledATokenBalance
      currentVariableDebt,
    }
  
}

I got a response like this

{
  "data": {
    "userReserves": [
      {
        "id": "0xe813e410f1841c06e40bff0407f7f4b63bc3ff360x7ceb23fd6bc0add59e62ac25578270cff1b9f6190xd05e3e715d945b59290df0ae8ef85c1bdb684744",
        "reserve": {
          "symbol": "WETH",
          "underlyingAsset": "0x7ceb23fd6bc0add59e62ac25578270cff1b9f619"
        },
        "user": {
          "id": "0xe813e410f1841c06e40bff0407f7f4b63bc3ff36"
        },
        "currentATokenBalance": "-313884125764640270",
        "currentStableDebt": "0",
        "scaledATokenBalance": "-312335331786059929",
        "currentVariableDebt": "0"
      }
    ]
  }
}

Why is scaledATokenBalance negative?

Start by reproducing the reported userReserves query for the supplied id and compare currentATokenBalance with scaledATokenBalance. The payload names no source file or test, so trace the userReserves indexing and balance calculation entry points; done means explaining the negative value or correcting it and verifying the query result.