We are using Case Feed and Email To Case. I am trying to figure out what the default value of 'From' is, it seems to be different from Case to Case.
From Our support teams need to send from different email addresses: (my emphasis)
The case feed setting "Specify From Address(es)" allows a default address to be specified for the case feed. If the department Users are assigned Case records types and page layouts, then each department may have a different From address.
The Users for department A will have;
Case Record Type: Team A
Page Layout: Team A
Team A Case Feed Layout from Address: support@teamAcompany.com
The Users for department B will have;
Case Record Type: Team B
Page Layout: Team B
Team B Case Feed Layout from Address: support@teamBcompany.com
That could certainly explain why users from different departments are getting different default from addresses.
When Replying to an Inbound Email Message on a Case record, what is the default value that populates in the FROM drop down menu field?
A Salesforce user can specify the sending address of the email in the From drop-down list for email addresses associated with Email-to-Case and Organization Wide Addresses, in addition to the logged in user's email address.
When creating a new outbound Email-to-Case message, the From address is auto-populated with the logged in user's email address. When replying to an inbound message, the From address is auto-populated with the routing address to which the email was sent.
If users need to use a specific FROM email address (such as an email-to-case address firstname.lastname@example.org), they will have to manually select it from the FROM dropdown list as there currently is no setting to specify a default reply-to/FROM email address for all outbound communications.