If I set a rule for auto reply of email messages with action 'reply to text'
and select 'reply to sender' only , then the option 'reply to all' is saved.
You can check this also to edit the action again and you'll see it is
automatically changed to 'reply to all'.
This is a bug since 8.0.1.

Major bug for end users unacceptable and a possible security threat

Anyone can confirm this?