No explanation returned on 28th July, 2021

[dd1929]

The API is returning an empty explanation string for the APOD on 28th July, 2021.

Date: 2021-07-28
Request URL: https://api.nasa.gov/planetary/apod?api_key=DEMO_KEY&date=2021-07-28
Returned JSON:
{"date":"2021-07-28","explanation":"","hdurl":"https://apod.nasa.gov/apod/image/2107/AM0644-741Full.jpg","media_type":"image","service_version":"v1","title":"Ring Galaxy AM 0644-741","url":"https://apod.nasa.gov/apod/image/2107/AM0644-741Full1024.jpg"}