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.
This is what my watch looked like the other day when I woke up (see below). The back plastic cover had slided off during my sleep (yes it is a very thin sheet of plastic/gorilla glass). I'm running with the watch and it clearly looks like the glue has been dissolved by sweat. So beware that this watch is clearly not sweat resistant! This is a big dissapointment for me as I bought it 10 monts ago and payed 450 USD for it in Denmark where I live. Now I'm waiting to get it back from repair, but I don't have high expectations as I'm pretty sure the fix will only be temporary, as new glue will surely be dissolved again.
For me this is dissapointmen no. 3 with Samsung. First I was not able to download a new Android version to my Galaxy S8, just because I bought it in Germany (neighbor country to Denmark), so I realized that this is how Samsung control the prices in Europe (or maybe globally), very clever. I was not aware of this because I used Apple products before I switched to Samsung. So not able to get the new android version and unwilling to jailbreak it and loose warranty, I eventually gave up and purchased a new Note 9 and today I'm using a Galaxy s10 (purchased in Denmark of course, which is one of the most expensive countries in the world, the S10 was over 1000 USD here when I got it).
Secondly I recently noticed that my Tab S3 has been bend slighty. I was shocked to discover this because I have really been nursing my tablet and always putting it in my incase case when traveling. So the construction with glass on both the back and front must be really really week. The sad part is that I bought it in Best Buy in the US, so it is impossible for me to return it to the vendor as we don't have Best Buy in Denmark.
And now after this third dissapointment with my watch I must admit that I'm now looking for another brand, preferably one of the cheaper chinese brands as I've been using way too much money on Samsung products. It is really a big dissapointment as I love Samsungs design and own a lot of their products, even my TV is from Samsung. But I can't keep on supporting them when I see signs of lower quality and their prices keeps on going up and up. It's a shame :-(