Fetching submission by ID returns 200 status code, but empty data

[hongyi-chen]

Not sure why this query returns an empty data, when the status code is successful:

https://api.pushshift.io/reddit/submission/search/?ids=1q9dxr

This is the Reddit post I'm trying to fetch: https://www.reddit.com/r/changemyview/comments/1q9dxr/i_am_against_affirmative_action_primarily_in_how/

Noticed this similar issue here, but I'm not using aggs: https://github.com/pushshift/api/issues/62