I've had no issues with my S8+ and Gear S3. Nor did I with my S7 edge or my previous Samsung watches (S2, Fit). Sounds like an uninformed guess.S8+
Swapped out the device this afternoon hoping its a defective battery. The BB guy tried telling me it was probably due too using it with the Samsung S3??? If that's true I'll be moving on from Samsung. I can't find anything that backs up his claim so I'm guessing he was just guessing.