I spend some time every day reviewing questions (including "close question" queue). If I select "close as off-topic", I usually get a sub-selection of options to move the question to another site: meta.SO, dba.SE, serverfault, superuser, etc. This is the correct behaviour, or at least the one I've come to expect.
However sometimes, randomly (I haven't figured out the pattern), the sub-selection is not available, I can still select "off-topic", but can't select to move the question to another site. The screenshot below demonstrates this. Selecting another option (e.g. "not constructive") and then "off-topic" again does not help.
Is this a bug or a feature?
EDIT: This screenshot is Firefox on Linux, but I have also encountered this with Firefox on Mac.