Depending on ambient temperature and which input mode you have active (e.g. 240p or 1080p), TVP7002 chip might get quite hot. It shouldn’t be a problem if the bottom ground pad is soldered down well, but I included a 14x14mm heatsink with adhesive tape on v1.5 kits to be taped on top of TVP7002 just to be sure. You might want to get something similar locally and see if that helps. There’s also a 3.3V regulator behind the display which runs warm, but it should stand quite high temperature before automatically shutting down.
A weak joint on some FPGA pins could also cause that behaviour, so that’s another thing to try if previous solutions won’t help. LEDs shouldn’t affect this issue.