Wrong "To:" Address when Replying

Hi,

I've set up a new IMAP account in Mail 6.6, and created two aliases by adding them to the appropriate, "Email Address", field in Preferences > Accounts.

As a test, I sent an email from the new account using one of the aliases as the, "From:", and the main account address (ie. the account to which the alias is attached) as the, "To:". It arrived just fine, and shows as being from the alias, as expected.

However, if I choose to, "Reply To:", or, "Reply-To All:" from within this received email, the, "To:" field contains the address the email was received by (the main account address) instead of the address the email was sent from (the alias). Additionally, the, "From:" drop-down menu is the alias—though I think this is expected behaviour.

I opened the same email in Mutt, and performing a, "Reply", or, "Reply-To All:", causes the correct, "To:", address to be generated by default: the alias.

I've viewed the headers and the, "Return-Path:", and, "From:", addresses are the alias, as would be expected. I can't find any reason why Mail would not choose the alias as the Reply-To address.

Is this a bug?