The instructions for preparers of Form 1099-R state "Generally, you must enter the taxable amount in box 2a. However, if you are unable to reasonably obtain the data needed to compute the taxable amount, leave this box blank."

Leaving the box blank is not the same as entering 0.00, but some computer programmer who probably has returns done at H&R Block was probably offended at some time by not having an entry in that field.  I wonder if IRS accepts whistleblower claims that suggest they audit every recipient of a 1099-R from that source.  If you sent a copy to the payer itself, it might shake loose some action to review their procedures. 

I think I figured out that the "blank Box 2a" I see for Phoenix retirees occurs when they originally retired on disability, even though now past age 65.  There used to be special rules for cost recovery by disability retirees, right?  But those disappeared decades ago.