This issue has come up previously and I found this thread Email Notifications for Forms
It is worth checking it - from what I can see, you are supposed to receive email notifications.
My suggestion would be to test and see - if someone manually assigned a task in the project to you, will you get an email notification? Are the settings on the project and your email notifications done correctly? no do not disturb settings are actively by error. If all of these are set up correctly, then please do engage with asana support so they can assist.
Hope this helps.