We have updated the Gains page inNovember 2020. The sums of the coins there are now based only on IN (purchases, mining, airdrops etc) and OUT (sales, losses, fees etc) transactions and deposits and withdrawals are not taken into account.
If you now have (incorrect because individual) deposits or withdrawals those will correct the dashboard balances, but they lead to incorrect balances on the Gains page.
Please have a look at your Missing Transactions Report and correct the white lines with the help of this article:
Missing Transactions Report
Afterwards the gains page balances should match the dashboard.