I fought this problem for months. I have found a solution. I bought a HDMI to Rca device on amazon and connected Roku to this device then to the TV via RCA cable that came with the device.. Bingo the problems gone.
Without getting to technical , It appears as some streaming has data that your TV doesnt like so the TV kicks the Roku device off the HDMI port. Since there is no data interaction between the TV's RCA connection and the Roku , the Roku never sees the TV's response thus the Roku doesn't react adversely and does not return to home screen.