- Form 8606 can be filed by itself when you are not required to file a tax return.*
- Form 8606 was not attached to the filed tax return, as required.
- Use Form 1040X to add or correct information on an already filed tax return.
Therefore, the 8606 should be attached to an amended tax return.
In my opinion, you would not be fined a non-filing penalty after filing an amended return for those years.
* See Instructions for Form 8606.
