How to clear Gmail warning questioning a users' trust in Asana?

We are a Google Suite for Education site and have enabled the setting documented here Configure an external recipient warning and it is creating a stumbling block for this feature doesn’t seem to list any ability to configure this option on a per-domain basis.

Whenever our users receive email notifications from Asana, when they go to reply, gmail prompts them with the message, “Make sure this is someone you trust. biglonghashvalue...q24n3@mail.asana.com does not belong to your organization and is not in your contacts.”

We’ve already implemented spam bypass domains of mail.asana.com and asana.com, but it doesn’t affect the display of this trust prompt.

Obviously, we don’t want the user to pollute their Contacts with these hash email addresses, but we also don’t want them to see these warnings. Has anyone found a solution to this in their gmail admin configuration such that asana.com emails are fully trusted?