- As an admin, set up TOTP as an auth provider at http://phorge.localhost/auth/mfa/
- As a user, add a first TOTP auth factor at http://phorge.localhost/settings/panel/multifactor/
- As a user, add a second TOTP auth factor at http://phorge.localhost/settings/panel/multifactor/
- Go to a Maniphest task and select "Sign With MFA" in the "Add Comment..." dropdown
- Realize you have to enter both auth factors instead of being able to select one of them
I ran into this problem, now other users also did.