Your tax return should report dividends paid to you from all sources. If one of your mutual funds paid you dividends and they are not reported on your already-filed return, then your return was incomplete. You should amend the return to include the additional dividends. Check your paper 1099-b to make sure it shows dividends from the missing fund, and then add them on your amended form if they are indeed missing. If you imported your dividend information, it's always important that you review the data to make sure it is complete.
