In the Singapore government travel restrictions there is specific reference to Chinese passports issued in the province of Hubei. This is probably linked to that.
FWIW, Australia used to identify place of issue on passport (eg Melbourne, Sydney etc) but that ceased a while ago. Now, whenever that question is asked on an immigration form (yes there are some that ask it), I just put Australia, before I used to write the place identified in the passport. Just because it is not used in some countries, doesn’t mean it isn’t in others.