Subsequent to my original post, i did come across the same language you posted
"For IRA's: "If you (or your spouse if filing jointly) received more than one distribution, figure the taxable amount of each distribution and enter the total of the taxable amounts on line 4b. Enter the total amount of those distributions on line 4a." (page 29 of IRS 1040 instructions)"
and as late as a week ago, TT was only following this language if there were multiple exceptions (e.g. a rollover to a Roth is a type of 'exception')
but in recent releases they appear to have adjusted the code so that if there are multiple distributions, whether they are 'exceptions' or not, they are listed on Line 4a per the language you site.
Line 4b, which is the critical one, has never been a problem
