Historical big_map API and contract big_map history return different values

[konchunas]

If I try to access big map at a specific level using its name in /contracts/ API I get different results to what I get if I request historical data at the same level using the same big_maps API.
Here is an example:
https://api.tzkt.io/v1/bigmaps/2013/historical_keys/1649387
https://api.tzkt.io/v1/contracts/KT1FG63hhFtMEEEtmBSX2vuFmP87t9E7Ab4t/bigmaps/ledger/historical_keys/1649387

2013 is ledger big map id of contract KT1FG63hhFtMEEEtmBSX2vuFmP87t9E7Ab4t

You can see balances values are different in ways I can't comprehend.
Is it a bug? Which one is correct?