Hey Chris, sorry for the late response again, though I think we’ve been communicating through our other channels!
Dubbel is in its early stages right now, so we’re only officially supporting YouTube. It’s a massive undertaking, but something we’re making a ton of progress in. We should have better support coming soon (but thanks for letting us know about Guardian – that shouldn’t be happening).
The changes made were actually by Google. They’ve recently required all apps to target higher SDKs, which makes HTTPS Filtering not work (unless through an app launcher like Dubbel).
One thing that should be of benefit is that Dubbel currently lacks 64-bit support, which we are planning to release in a week or two. That will probably fix the issue with Chrome.