When switching back to Telus Optik from Roku ,we get no sound unless we reboot the Telus box
Can you provide more information? Is this a TV with Roku built in or a USB dongle?
I assume your Optik box is connected via HDMI. Have you tried unplugging and reconnecting the HDMI instead of rebooting? This will confirm it's a HDMI handshaking issue when switching inputs and it's also much faster than rebooting the Optik box.