Reorted change in behaviour for "sub structures"

[jamesbwestwood]

Email about issue with API:

A new issue with the covid dashboard appeared today. When making queries that include structured data with sub elements (that is {case:{new, cum}, deaths:{new, cum}} or similar), the following exception is returned:
{"response":"An internal error occurred whilst processing your request, please try again. If the problem persists, please report as an issue and include your request.","status_code":500,"status":"Internal Server Error"}
The following query was used:

https://api.coronavirus.data.gov.uk/v1/data?filters=areaType=nation;areaName=england&structure={%22date%22:%22date%22,%22name%22:%22areaName%22,%22code%22:%22areaCode%22,%22cases%22:{%22daily1%22:%22newCasesByPublishDate%22,%22cumulative1%22:%22cumCasesByPublishDate%22},%22deaths%22:{%22daily2%22:%22newDeathsByDeathDate%22,%22cumulative2%22:%22cumDeathsByDeathDate%22}}

If a query without sub structures is used, the API works fine.

https://api.coronavirus.data.gov.uk/v1/data?filters=areaType=nation;areaName=england&structure={%22date%22:%22date%22,%22name%22:%22areaName%22,%22code%22:%22areaCode%22,%22daily1%22:%22newCasesByPublishDate%22,%22cumulative1%22:%22cumCasesByPublishDate%22,%22daily2%22:%22newDeathsByDeathDate%22,%22cumulative2%22:%22cumDeathsByDeathDate%22}

This bug is new, since I was able to use these queries yesterday.