Hi @anon42402854, welcome to the Asana Community Forum 
Thanks for flagging this! This was a bug that has now been deemed as solved: When logging into desktop app, doesn't redirect back to app from browser to authenticate
I’m sorry to hear that you’re still running into issue! Our Engineers have suggested reaching out to our Support team with a screen recording of what you’re encountering so they can investigate further.
You can contact our Support team by following these steps: https://forum.asana.com/t/new-how-to-contact-support-thread/87842