I've put about 1000km on the 830 and I am mostly impressed with it compared to my 800. I've had a couple of glitches where one of the sensors, usually the cadence sensor didn't connect. I would have to go to setup, sensors, choose that one and press connect and it would work.
This morning on my way to the office I started the navigation and got the first prompts to get out of my neighborhood. All as normal. Once the route was loaded and I started riding it I switched to my normal screen with speed/cadence etc. I noticed that there was no cadence. I figured it was the same thing as before so I went back to the main screen and saw that my cadence and speed sensors were both not connected. I went to each and pressed connect and they came up. I went back to my user screen or whatever it's called and could see my cadence was fine. But at the next intersection, I got a TBT to turn there. I was supposed to go straight so I ignored it and got the next one. I don't know if it was trying to route me back to the start or just lost. A u-turn would have brought me back. I stopped the course and restarted it. It asked me if I wanted to navigate to the start and I killed that. It found the route and worked flawlessly.
I purposely use the TBT Navigation on my daily commute or know routes to verify that it's working rather than getting surprised when I'm somewhere that I don't know.
There's the question about the sensors not connecting but I'm also wondering if there's an issue going back to the main screen during navigation? Has anyone seen this sort of behavior?
I was using version 3.5, connected to my iPhone 6.2 with the latest GC software. I just installed the beta update so I'll see if this helps.