Group Projects API include_subgroups flag doesn't show projects in a subgroup

Summary

I was trying to get a groups repositories including repositories in sub-groups. I attempted to use the include_subgroups option that is in the API docs but it doesn't seem to do anything.

Steps to reproduce

I have an organization setup to test this scenario. I would have expected the following API call to fetch 3 repositories, but it only gets 2.

curl -H 'Authorization: Bearer xxx' 'https://gitlab.com/api/v4/groups/sticklerci/projects?simple=1&include_subgroups=true'

I also attempted to fetch sub-group projects from the gitlab-org without any luck.

curl -H 'Authorization: Bearer xxx' 'https://gitlab.com/api/v4/groups/gitlab-org/projects?simple=1&include_subgroups=true'

The pagination headers with and without the include_subgroups parameter are the same, and I would expect there to be a difference as more projects should be included.

Example Project

https://gitlab.com/sticklerci

What is the current bug behavior?

No projects from subgroups are returned

What is the expected correct behavior?

Should see projects in subgroups

Relevant logs and/or screenshots

N/A

Output of checks

This bug happens on GitLab.com