ACF 2021: Can't Check Maintain Connection to Mail Server
I am running ACF 2021 (2021.0.18.330341) standard edition, and attempting to configure mail settings. I noticed something strange where, when I check the box "Maintain Connection to Mail Server" and then "Submit Changes", the box shows as unchecked, despite seeing the green "Server has been updated successfully" message:

This feels like a bug to me. Can anyone else confirm if they have the same issue.
I tried enabling TLS connections on and off to see if it made a difference. It does not.
Note: I have a successful connecction to the SMTP server and can send mail fine. The reason why I want to enable this setting is because we frequently send out a "burst" of emails at once and read that enabling this feature is recommended.
