I'm on Beta 8.6.230 on a 2019 ShieldTV Pro. When I launch Channels for the first time, after a reboot or "dismissing" the app, I sit at a blank purple screen for about 10 seconds. I then get the spinner for about 1 second and then the UI loads. I've seen this in the Alpha as well, which is why I dropped back to the Beta. Once Channels has launched, I can switch back to it with no delay. It is consistently reproducible.
I'm not sure at what point the logging is enabled in the app. I can't access it by IP:5700/log?show=all until the UI comes up, and I only see 2 seconds of logs so I'm guessing logging isn't running when the problem is happening. Don't know if it's related, but I see these two lines in the log on the client:
08-06 15:39:13.372 27392 27412 E Fabric : io.fabric.sdk.android.services.network.HttpRequest$HttpRequestException: java.net.ConnectException: Failed to connect to settings.crashlytics.com/0.0.0.0:443
08-06 15:39:44.038 27392 27459 V ApiServer: REQUEST: GET /log
08-06 15:39:44.068 27392 27459 E fi.iki.elonen.NanoHTTPD: Could not send response to the client
08-06 15:39:44.068 27392 27459 E fi.iki.elonen.NanoHTTPD: java.net.SocketException: Broken pipe
Update: I did a force stop and clear data on the app. When I launched it, I still got the blank screen for about 10 seconds before the "Welcome to Channels DVR" screen appeared.