Possible bug with -implode

Since Imagemagick 5.5.4 to 6.3.0 the following command:
    convert -size 320x240 -depth 8 gradient:red-green
-implode 3 file.jpg
makes a picture like the first one attached to this email.
With 6.3.1 and 6.3.2 the same command makes a picture like
the second one attached.
Is this change intended or is it, most likely, a bug?

Giacomo

_______________________________________________
Magick-bugs mailing list
Magick-bugsimagemagick.org
http://studio.imagemagick.org/mailman/listinfo/magick-
bugs