The API description for /instance/getAttributeType in Swagger doesn't work

When deployed as part of the ADOxxWeb API the /instance/getAttributeType operation does not have a functioning description in Swagger:

Trying to execute this leads to the error: TypeError: Window.fetch: HEAD or GET Request cannot have a body. Entering an attribute ID instead of "string" leads to the same error. Using CC "Core" GET_ATTR_TYPE through /dao/execute for the same attribute ID returns the correct type ("result": "STRING")