Here is a list of issues I have had since update to 15.
• HR is not working properly (very intermittent)
• keeps losing connection with phone,, (Galaxy 8+)
• lag on button press (scrolling through main screen and others)
In frustration I did a reset to defaults and now I don't have the ability to get any other watch faces. The phone and watch will not stay connected or sync.
Thanks
WP