Can't share project with subgroups

Summary

I don't sure it's a bug, maybe this is feature that needs to be implemented. I have a project in group that I am the owner and I have subgroups that I want to share the project with, but I can't.

Steps to reproduce

• Assuming you are a owner of a group

1. Go to Project's Members option in https://gitlab.com/NAMESPACE/PROJECT/settings/members
2. Click on "Share with group"
3. Type anything in the "Select a group to share with" textfield
4. No subgroup appears

Example Project

I create a new group, A project in that group and a subgroup, but I can't reproduce this problem, so I think is a problem with groups created in a old GitLab version maybe?

What is the current bug behavior?

I have a project in group that I'm the owner, I have subgroups in there that I want to share the project with, but I can't. When I tried to search them, I doesn't find them.

What is the expected correct behavior?

The subgroups that I'm the owner too.

Relevant logs and/or screenshots

Subgroups:

Share with groups page:

Output of checks

This bug happens on GitLab.com