Please test d-i netboot installer 20101020ubuntu525 or later; or tomorrow's server images with a timestamp of 1st of December or later. It should resolve your issue. Please comment if your testing was successful. Then we can look into cherry-picking this fix for xenial upcoming point release too.
Please test d-i netboot installer 20101020ubuntu525 or later; or tomorrow's server images with a timestamp of 1st of December or later. It should resolve your issue. Please comment if your testing was successful. Then we can look into cherry-picking this fix for xenial upcoming point release too.