@useroOTnBSXL2t Have you tried clearing the cache partition on your phone? Here are the steps.
I would be happy to look into your concerns.
Can you please send me a private message with the below information here at this link: http://bit.ly/2GH8URL
(15)Digit IMEI Number:
Mine is the same. Turn off the volume every night and when I turn it on in the morning the messages remain silent. I just have the standard S8 and use the standard messages