I'm getting the same exact thing. I've seen this with previous
versions of backmyfruitup and thought that version 3 might get rid of
the issue but it didn't. During version 2 I started with the
sparseimage that BMFU created. Then after a few weeks to a month later
I got a new image. I ignored it and let this image do its thing and
then after a few weeks an even a newer image was created. Since
version 3 I've had it create a new image once. Does anyone know why
this might be happening?