Chroma subsamlping 4.4.4

[Orion3000]

First I wanted to thank you a lot for the latest update amazing work as always. I had a small issue with the latest update. When I use the NVENC with AV1 and select profile level high444 and select sampling 444 and select 10 bit everything works fine except media info report the Chroma as 4.2.0 instead of 4.4.4. I tried to encode using high444 and sampling 420 and both gave me the same result as Chroma 4.2.0 and not 4.4.4

 This issue doesn't happen with h265 so my question is it the AV1 fault or is it something wrong with the latest update? I have a RTX 4090 GPU if that helps. 

Again thank you so much for all you do.