1. That's the final lens you are looking at,
2. It's a lamp, but as long as it works, no need to replace it, especially only after two years. How many hours?
3. The owners manual won't tell you anything, you need the Service Manual,
4. Look at that corner of the screen and see if anything appears out of place.
My guess, it's something in the internal optical path of the 'light engine' which would require disassembly. I never heard of this before (not to say it hasn't happened). I have a thread on lens cleaning that is in the sticky at the top of the page you should look at. It's for a older series, but should be close enough to work with if you have some mechanical/electronic experience.
Abundant OTA television is what makes this country different from all others. Lets keep it this way. If you like Wi-Fi so much, OTA fits right in. After all, it is wireless.