No , as the V3 box was showing no issues when I tested it on the S90C, so to say the the V3 box was faulty with that tv would be incorrect.
What I will say though is there IS an issue between Sky Q box HLG and Various Samsung tv sets ,and as you have acknowledged on the other forum Vincent T has confirmed that the S95C under tracks with HLG content , and also on the other forum another member has also stated that he also went from a V3 to a V2 box and confirmed the picture quality was indeed improved on his S95C ,it was still much dimmer than it should be .
I honestly do not understand why you constantly try to defend Samsung issues , especially from users who have experienced the issues , when you have not even had the same set in your home , do you really think I would have sent the 77" S90C back after 24hrs at the price I paid for it unless it clearly looked very poor with HLG content in comparison with my 77A80J using the same Sky Q box ?
Please either try an S90C/S95C or stop constantly defending Samsung , as they ar FAR from perfect .