Invoking my Google action produces inconsistent results. Sometimes it'll work normally, and sometimes it'll just say "app isn't responding right now. Try again later."
When it doesn't respond, the error in Stackdriver logs states:
MalformedResponse: ErrorId: 9d77f434-ed3c-485b-9531-05449ee83c29. Failed to parse json into AppRequest proto. com.google.protobuf.InvalidProtocolBufferException: Cannot find field: canvasContext in message google.actions.v2.Input
This error has happened on the google home, google home mini, and the Lenovo smart display. It happens most on the smart display. And it hasn't happened yet on a mobile device.
I see exactly the same error in some of our customer projects. For me it looks like a Google hiccup because our AoGs with that error in the logs does not even use Canvas.