When something goes wrong during a password change, tl-passwd tries to displays the entire message on one single line. Often, this means that only parts of the error message can be read.
Re-targeting to 1.7.0. What I've found out so far: I think the problem is that a very long line is returned from PAM, that is: pam_winbind. I've not been able to find any long strings with pam_unix. So, the best way to check this is probably to setup up a machine that authenticates against AD. Also, there are functions in tldialog that can be useful. The tl-setup uses tldialog.format a lot, but it actually makes things worse: It *removes* (single) line breaks and replaces them with spaces. The (currently unused) function tldialog.break_lines might be just what we need for this bug, though. (As a side note, tldialog is a little bit un-generic: It contains hardcoded strings like "installer" etc. It should be more generic.)
tl-passwd has been removed from the product.