Hi @anon84874474, welcome to the Asana Community Forum 
I recommend reaching out to our Support team directly here as they have access to additional tools that we don’t have here on the Community team to look into the projects and tasks from the back-end.
My hunch is that the issue may lie with Custom Fields in the project, but our Support team can confirm if this is the case!
You can reach out to them by following the steps below! You can also provide them with the URL link to this thread so you don’t have to repeat the issue 