Several years ago I inherited an IRA (now a Beneficiary IRA). I took the annual RMDs based on the decedent's age, as required.
However, I didn't enter any 1099-R forms into TurboTax, since they didn't seem to impact my taxes for that year. I doubt I can reconstruct the history of those 1099-R forms now, since this has been ongoing for some time now. With a lot of effort I might be able to find most of them, if necessary.
Are there implications from this that I will need to deal with, now or in the future?
It depends.
If you were issued 1099-R forms in the past, you were required to report them on your tax return even if the amounts were not considered taxable income.
I recommend amending your prior year returns to ensure you correctly file your tax returns as 1099-R forms are also reported to the IRS. This will ensure you correct your tax return reporting before the taxing agencies issue a notice to you as the income reported on your tax return will match the source documents sent to the IRS. It also ensures your return is accurate as there could have been tax due based upon the type of retirement income you inherited. The IRS provides more guidance on determining RMD amounts for beneficiaries in this link.
If any of the amounts were taxable, you are liable for the taxes still owed on the income and could be subject to interest and penalties on the unpaid amounts. Please see the following links for more details on amending.