Thank you for your help. I only it were that simple.
In both the before and after there are 6 columns in each row, which is a good thing because I cut-and-pasted the row.
And because the table is Auto-fit to Contents, Word is setting the columns widths -- presumably the same for each row. (Though I suppose there could be a bug in Word that means the columns are imperceptibly different.)
Since my original post i discovered that if I shorten the 4th column of the sixth row so that there is no word-wrap that the problem does not occur. And I noticed that the (incorrect) widths for the pasted row are likely not random -- Word has aligned the right hand side of the 4th column with the right hand side of the 6th column of the rows above and below.
This is not a huge problem - I can fix it by selecting the table and asking Word to first distribute columns evenly and then to Auto-fit again. But it is a pain.
Is there an official Word bug list anywhere? Or place to submit one?
Any additional insight appreciated.
Thanks,
Mike