We do not guarantee this receiver will work with Pioneer KURO LINK-compatible components or components of other makes that support the KURO LINK function. We do not guarantee that all synchronized operations will work with components of other makes that support the KURO LINK function
ARC and CEC lines are separate hdmi lines. however the CEC protocol is used to setup the ARC connection between the TV and the AVR. CEC commands like Initiate ARC, and tell me what codecs the AVR supports are used.
If your receiver doesn't support ARC it still might support System Audio Control where the TVs volume bottons will control the AVRs volume when connected. This is useful still useful even if your connection between the TV and the AVR is optical. In the CEC setup on the Roku TV, you can turn on SAC and disable ARC so the Roku TV won't try to initiate the ARC connection.
From my look at the Pioneer manual, Kuro-Link is Pioneers version of CEC.
It HDMI3 is the ARC port on the RokuTV, try using a different port.And what firmware version do you have with the RokuTV?
I've submitted a new bug report for this, and included the forum information.
Here are some other things you could try instead of restarting the TV.
1. Try power dow/up of receiver.
2. Unplug hdmi cable (either end) between AVR and TV, wait 3 seconds, then plug it back in. I know this is inconvenient, but it might do as a workaround.