Messages app not staying on known senders only filter

I always leave the messages app on the known senders filter. However lately when I receive an unknown message, the message app switches the setting to all messages so when I eventually open the app it is no longer on known senders only. I have turned messages on and off in settings, rebooted, etc but nothing has fixed it. Is this a known bug? Does anyone have a fix?

[Re-Titled by Moderator]