Galaxy S5 ringtone changing by itself

[AC Question]

Hi, I hope an expert here has an answer to this....
I've got a new Galaxy S5 purchased earlier this summer, and almost from the beginning I noticed this irritating issue. Every couple of days, the ringtone will change by itself. I deleted the ringtone that the phone was switching itself back to, and that didn't do anything. Now it switches back to the one I set it on after I deleted the first one (yes, I'm one of those who likes to change ringtones from time to time). Very strange. I'm hoping someone else has heard of this and has a fix.

Thanks