After the recent GC update, I tried uploading another one of my indoor training rides from my Edge 305.
Like the previous version that supposedly supported indoor activities, GC does not display the cadence graph, nor does it appear to store the cadence values in the backend DB. Cadence values don't show up when the activity is exported, so this appears to be an import problem, not a display problem. It also means that uploading indoor activities now is more or less pointless.
I'm very frustrated and disappointed that new features (calendar) and new business partnerships (health) have been released without addressing fundamental bugs like this. I've been waiting for indoor activity support for close to three years, and it's still not here.