Thanks for your post.
Sorry to hear about the issue you are experiencing. As mentioned by @AvsGunnar, in some cases the USB power provided by the TV is not sufficient to power the device. Even though your Roku device may appear to be working, running with insufficient power can lead to instability, crashing, and other unpredictable behavior.
If you have suspected that the TV itself has the problem, if possible, we suggest you try to plug the device into another TV and if there's any difference after.
See related support link: What to do if you cannot see the picture from your Roku streaming player on your TV
Keep us posted on how it goes.