Similar issue. im running ios10 beta, girlfriend running latest ios both on iphone 6. I have 4 lutron switches, multiple hue lights with bridge 2.0, august lock.
I can see and control everything via siri and the apps. When I share access with her phone, she can see the lutron and august via 3 party apps like elegato eve. When I go to the hue bridge and lights in that app, they all show up in the app, but have a red triangle next to them saying unreachable, even though the app shows all of my lights and bridge.
She can control the lutron and august via siri, but not the hue. She can control the hue directly from the hue app.
I have tried deleting, resetting, logging in and out of icloud. It was working before I installed the beta, so maybe its a hue vs beta configuration issue?