I have same box 4a problem as Miranda57.
But in my case it is the 1099-R pension amount not included in 1040 box 4a. My 1099-R IRA distribution is the only amount included in box 4a. Box 4b does properly include the taxable amounts summed from both 1099-R forms.
The "Taxable amount not determined" is checked on the IRA distribution 1099-R but not on the pensions 1099-R, but I don't think that should have any relevance.
