Hello and thanks for posting!
The relevant links that should help you clear the issue up can be found below.
Here’s the relevant part of the docs you will want:
https://osc.github.io/ood-documentation/latest/customization.html?highlight=home#custom-error-page-for-missing-home-directory-on-launch
And there is a separate Discourse that goes into more detail:
It essentially has to do with when that $HOME directory is created and trying to access it before that happens, and how to make sure it does get created for the user if they try to access it before it exists by providing an error page that allows the SSH session to start and create the $HOME for the user.
Hopefully that will help clear the issue but please let me know if you need any more help or guidance