Bose Bluetooth headphones allow 2 devices via the app so you can coñnect smart phone and LG TV can your headphones do same? The other way is try 3.5 plug in Bluetooth adapter in your LG TV sold by eBay or Amazon see if you have same problem.
I can say my lg49uh850v keeps dropping Bluetooth connection hence I use Bose app but no distortion issues
Maybe something in your house something is affecting Bluetooth connection