weirdness with jit.dimmap(or is it jit.iter?) +zl group

I have an 8 * 8 single plane matrix that I am sending through
jit.dimmap, jit.iter, and finally zl group.

The matrices appear as expected when displaying their content in
jit.pwindows. The original matrix creates a list with the values in
the place I expect. However, the dimmap matrix has odd integers in
the list. Ints consistently appear in places that are unexpected.

Below is an example patch.

max 5.0.5, osx 10.5.5, early model macbook pro