Creating Client Project WITHOUT Adding Client User

Creating Client Project WITHOUT Adding Client User

Hi there! I'm trying to add a Project to a Client Contact. I do NOT want that Client to have access to the project. When I select "none" for Client Users, I get an error message "Sorry, there was an error. Please try again later". If I add the actual client to the project, it works just fine. To be clear, I do NOT want any client getting any sort of notification as our goal is to use this for internal projects that are related to that client. If you can assist with this issue, can you also help with whether it's possible for the add project screen to default to "none" for client user? 

Thank you!