I assume that you meant to say that the entirely taxable $44,000 was on line 4b, not line 4a, on the originally filed Form 1040. I'm not sure that there are any cases on a 2018 Form 1040 where the $44,000 would be on both lines 4 and 4b.
On your recreation, it seems that one of your Forms 1099-R has the IRA/SEP/SIMPLE box marked and the other two do not, or vice versa, and you somehow indicated that either the $11,000 distribution or the $24,000 distribution (or both) was not fully taxable.
Which Forms 1099-R have the IRA/SEP/SIMPLE box marked?
Do any of these Forms 1099-R have an amount in box 2a that is different from the amount in box 1 (or has a blank box 2a)?
Is any Form 8606 present in your recreation?
You could try deleting and reentering Forms 1099-R to determine which one is being treated as not fully taxable.
The difficulties that you had trying to amend from the original tax file suggest that the file had been modified between the time that you filed and the time that you began the amendment process (or perhaps you inadvertently had initiated the amendment process before filing the original return, locking in values from an intermediate state of your tax return). You'll want to make sure that the PDF that you have really does reflect your actually filed tax return. You can obtain a transcript of your filed 2018 tax return from the IRS online: https://www.irs.gov/individuals/get-transcript
