Emails to mailbox alias delivered to alias, not primary address

[Bolton]

Emails from within our 365 tenant always get resolved to the primary address. When an email from a PowerApp is addressed to a mailbox alias, the received email has the primary address in the recipient field, not the alias.

We have processes running on mailboxes that look for the alias as a trigger. We would like the option to ensure that the email arrives in the mailbox addressed to the alias.