Mysterons is probably correct - the only way that the 'D' in the third column could be considered to be a displaced letter would be if thematic words 'pushed' the letters below them down, rejoining again at the top of the column as they are pushed off the bottom. However, as has been correctly pointed out, this would mean that in columns 6 and 7 the letters in row 8 would be AA, so the 'principle' would not appear. In addition, the 'N' at the foot of column 8 would also be pushed round, so there would be nothing to stop the sixth movement reaching the same level. To allow this interpretation for column 3 alone would be inconsistent, therefore the 'D' in that column should not be displaced.
PS The alternative to always keeping their original order could be jumbled up / entered alphabetically / in reverse order, for example.