I fixed issue by unplugging used composite connections to free them up then moved around connections until I got it working. I had a friend watching the screen while I fiddled with the connections until it worked
You can also go into the settings and there is an option for "Restart", which will reboot the TV and bring it back to its normal colors on the home screen/menu etc. This is NOT the reset to default/factory...So make sure you use the "Restart".
I had the same problem with a Roku Streaming Stick +. I tried multiple interventions as noted above and elsewhere including power cycle, restart, checking TV color settings, alternative HDMI input, factory reset, etc., none of which worked. I reported this information to Roku support and they agreed with my guess at a hardware problem. After determining that my device was 3 months out of warranty they suggested that I purchase a new unit on Roku's website. Obviously not what I was hoping for. After purchasing a new unit (at Best Buy on sale), I turned the old one on one more time and low and behold it was back to normal color. I watched a whole movie without problems. My best guess as to why is over heating. I usually had the unit powered from a wall plug, and one of the last things I had tried was switching to TV USB power, which made no immediate difference. With TV USB power the Roku device powers off when the TV is turned off, rather than always being on with wall power. A guess is that being off for a longer period allowed cooling down and returning to normal function. Who knows how long it will last, but it is one more thing to try. Note there will be some delay for Rokut Stick to power back on, but worth it if it keeps working.