I have notice Samsung has no solution to this problem !!
I have had this Galaxy watch for 9 months and the rear heart rate sensor cover has come loose also. I had the same problem with my S3 watch, with the back plate disk coming loose. These waterproof watches are obviously not perspiration proof !! And it looks as though Samsung will ignore this problem. Well what does this tell me about Samsung support for watches, phones and tablets, which I have all ? Stop buying defective Samsung Products ???
Is This My Solution Samsung !!
The samething just happened to me. The sensor just came off. Today was a super humid day. Reading all of post about this issue I'm fairly disappointed in how Samsung is handling this. To be told water damage on a watch that's water resistant is the most absurd thing I've ever heard. On top of that the watch is about 9 months old.