import_export: "no repository" message upon project import (into a group?)

Summary

This was primarily discussed in #23833 (closed) by @Dannylee12, @wjdp, @jameslopez and then me.

Basically, I exported a project from gitlab.com and imported it in a fresh docker instance (8.14.4).

In my case (not sure for the others, please contribute to the discussion :), when I imported the project in one of my user's group, I got the following message in the Repository tab:

It does not happen if I import it in my user's namespace. And unfortunately, I just tried to replicate it and it didn't happen again…

According to others' reports, if one clicks on the create empty bare repository, then the actual repository appears as if it was always here.