Get historical portfolio value: returning incorrect balances for ETH and MATIC


portfolio_v2 endpoint (GET /v1/{chain_id}/address/{address}/portfolio_v2/) shows incorrect historical balances for native tokens on Ethereum (chain_id=1) and Polygon (chain_id=137) networks. The respective balances of ETH and MATIC shown in the response are the balances of today throughout the history, not the actual historical balances.

I have tried this with several addresses and the API returns consistently incorrect values. As for other than the native tokens (ETH and MATIC), such as UNI or WBTC for instance, the values seem right.

Reproduction steps
Example address: 0xb5bc886ebff2224d9fbedcd6a5fd0e7d6a28da11

Go to Polygonscan: Address 0xb5bc886ebff2224d9fbedcd6a5fd0e7d6a28da11 | PolygonScan

  • on 15th of November 2021 the address holds 7.559 MATIC
  • on 13th of November 6 MATIC was sent from the address, meaning that before this transaction the balance was 13.559 MATIC

Whereas the response from the API shows that the balance of MATIC was 7.559 each day.

Expected result

MATIC balance for this specific address should be 13.559 on the opening of 13th of November and some days before that.

Actual result

MATIC balance of this address on the open of 13th and before that is is incorrectly 7.559, being the same value as today.