I bought the oled65c7p and I have the same problem just with the tv, no sound bar or other sound equipment. The tv picture is way ahead of the tv sound. It seems to get worse over time. All of the adjustments result in a temporary fix and it eventually reverts back to the sound being way behind the picture, so much so that the -5 adjustment is not enough. I did find that disabling the Dolby output from my directv box and changing it to pcm results in a synced sound and picture. But now I don’t have Dolby sound, just stereo. It seems the LG tv can’t proess the Dolby signal from the satellite box, my Samsung tv did not have this problem.