This issue affects accounts that have both Multi Brands enabled and have installed the Zendesk-made app "Select an Address". Additionally, all Agents in the account work across brands, so groups can't be used to filter, nor can the option to "use last address", since it may not be in the correct brand.
The goal is to ensure that email domains always match the Brand by default unless an agent intervenes and chooses to configure it differently.
Ideally, if you have both features enabled, an agent manually creating a new ticket would choose a brand on the left side of the ticket (required) and optionally choose to modify the sender address with the app on the right, but if they made no changes to the "Select an Address", then the default email for the brand they chose would be used.
This would match the behaviour of the "Select an Address" when used without Brands enabled, So the account only has a single brand. In this case, it can be optionally used, but if ignored on new manual ticket creation, the email address set as account default is used, and of course, since only one brand is in use, it matches.
Currently, what happens when both Multi Brands and "Select an Address" are used and an agent does not take the extra step to choose the email address is first or primary brand is default email is used. Example of what currently happens:
Brand A and Brand B exist in the account. Both brands have a default email configured in the brand admin area. Brand A was the first one created (not sure if the order of creation matters).
An agent chooses Brand B when manually creating a ticket but fails to manually adjust the "Select an Address" app. With no adjustments, when the agent submits the ticket, the "Select "Send As" Address" will change the email to Brand A's default email, ignoring that the brand of the ticket was set to Brand B.
