Nokia has posted a minor update to the Nokia Here Transit app from version 5.0.2197.0 to version 5.0.2231.0.
Given the small increment in version numbers and the lack of a change log the update is likely of the bug fixing variety.
The update appears to address an issue where the app stopped loading data from some regions, making it somewhat useless.
Find the app in the Windows Phone Store here.
Thanks Rui for the tip.