Have problem with mine 945 and edge530. Stupid Garmin. I have Garmin devices for 2000$ at home and they work as ***. HRM TRI disconnects from Edge 530 or 945, first 945 died in two days after purchase, Garmin Scale Index always show different numbers during one minute(also was replaced by the warranty. Ox sensor on 945 is turned off because it shows stupid numbers (moon phases or index Dow Jones). i had during 2 years about 4 HRM belts because they die in one day without even saying anything. You have to handle them like an ancient book-because they cost 100$. Aliexpress watch bands are more comfy and does not leave any problems on the skin and cost 3-8 usd vs Original 25-40 usd that are made of hard rubber.
i Was Your fan so long. Maybe i need to sell all Garmin devices in my home and to buy POLAR or SUUNTO or COROS.