Installed HS210 kit. Using HS210 as primary and standard 3-way as auxiliary works properly. Replacing standard 3-way auxiliary with 2nd HS210 from kit and pairing them together as instructed in app (hold button until WiFi light flashes red & orange) yields the scenario where the primary switch and the app work fine but pressing the auxiliary switch results in that switch and the light they operate flapping on and off at a rate of about 2x per second. I've since uninstalled the auxiliary and gone back to a standard 3-way in that location but would like to know how to get the 2nd smart switch to work properly as auxiliary.