Hi, (Looping the patch author into this bug.)
Turns out it seems to be caused by #983623, which is to provide scripts to set up ibus-mozc after the installation of the package, and according to my understanding, this is unrelated to gnome-initial-setup package. While I can understand that this patch is to serve Japanese users of Debian and its derivatives, in our case we need ibus-mozc to be installed in the system but not activated automatically so the image can serve users using different languages. I think either we can fix the script so ibus-mozc won't get set up if LOCALE is not ja_JP, or we should remove the script completely and require users to set it up (which is the case for other IBus engines). Thanks, Yao Wei