Yes, U6 and U7 get very hot on my OSSC.
I’ve spent a lot of time reflowing and reconnecting most components on my OSSC. I’ve fixed the issue the unit was having with resetting itself, but I now have ongoing problems. I’m not sure it’s a sync problem though – the LCD display continues to display the incoming signal info (which means it hasn’t lost sync?). The issue on this OSSC that the red LED lights up and the output signal is dropped.