Cherries in outer cells?

The description says "new cherries can't appear in the outer cells", but several times, I've gotten maps that look like:

['..T....T.C',
 '.......T..',
 '...TTT....',
 '..T....T..',
 '..T...T...',
 '.0T..T....',
 '.1........',
 '.2.T..TT..',
 '.3..TT....',
 '.4........']

Is this a mistake, or is there something I'm missing?