Are you using the keyboard with or without ART? just curious if its an ART thing.
The error message I would say is definitely a software conflict... With G2 when they did the KitKat update I got that message with at every boot with Swiftkey. Only when Swiftkey heard enough complaints and two updates later it was resolved.
Go backwards and uninstall your apps you put in recently and reboot and see which one caused it and report it to the developer. and if you enabled ART, disable and see if the error remains... Like Chromecast and casting... seems I can't cast because I have ART enabled but those that don't have no problems.
Yeah, sucks about cast because I think that's one of the coolest new features. But I havent found myself needing it so I can wait for a hopefully soon update to fix it. It's the only glitch I've had with ART.