Shared users not listed in the Form-Sharing page

In our self-hosted server, we have a form with permission given to about 7000 users.
The sharing permission was granted using the python script [ asset.assign_perm(userobj, perms) ].
Now none of the users are listed on the Settings > Sharing page for the project.
Still the users are able to login, view and submit the form without problems.
But the problem is in changing the permission for a particular user – the user is not listed at all in the sharing page and hence cannot be edited!

My doubts are:

  1. Is it happening because the number of users to whom the form was shared is large?
  2. Or is it because user permissions were added through scripting? But users added through interface are also not listed!
  3. Since many users were added through scripting, can user permissions be edited for all users only through scripting?
  4. Is it a bug in the user interface for showing the sharing permissions of the form, when user number is in thousands?

(KoboToolbox was installed on our server from github in December 2023 – so I guess it should be a very new version)

@kpk_in, I would say sharing 7k submissions is way too large to handle.