Create muc Room with a Subject

I am working on an elixir module for ejabberd. I am trying to create a MUC room and give it a subject from within the module.

I have tried to use
:mod_muc_admin.create_room_with_opts(..., ..., ..., [{"subject", "my subject"}])

I am able to create a room fine and even change options like title and persistent. However, when i try to set the subject it is just not working. I do not even get an error.

I have not seen any other way to create the subject programatically on the server side.

I am using 16.9 version of ejabbered.

Any help is appreciated.