Open Radar

 
Summary:
Calendar invitation reply emails are not sent from the correct account but from an arbitrary email account.

Steps to Reproduce:
- A Google Calendar invitation is received on a (non-Google) IMAP based email account, e.g. with the address foo@bar.com.
- The (first) ICS Attachment of the invitation is double clicked and opened in the Calendar app.
- The calendar is changed from the default Local calendar to an iCloud based calendar (this step doesn't actually make a difference).
- The event is accepted.

Expected Results:
The reply email should be sent from an email account with the From address foo@bar.com, if available.
Alternatively, it would be fine also if the reply email would be sent from the iCloud server side, the same way as iCloud calendar invites are sent. 

Actual Results:
The reply email is sent from an arbitrary email account with a completely different From address.

Notes:
It looks like macOS selects the last account in the list of accounts to send the reply email. When I disable the wrongly selected account, macOS selects the next activated account from the bottom.

Regression:
This used to work. I checked my Sent folder and the last correct reply was sent in August 2015 (from the then-current Mac OS X).

See also:
rdar://30309747 Calendar replies contain "(null)"