Countdown URA - StopCode1 errors in some stop locations

Alert: Issue relating to the Countdown Unified Realtime API:

Due to a change in a downstream system, the field ‘StopCode1’ will return errors for a small number of stop locations.
The cause of this error has been identified and will be rectified in the next scheduled Data release on 7th July. In the interim any query requesting or using this field as a parameter is likely to be unsuccessful.

TfL apologies for any inconvenience caused while this issue is resolved

[EDIT: we were not able to fix this issue on 7th July (as originally stated here), the fix will now be rolled out (overnight) on Friday 14 July - please see latest post relating to this here]