Multilevel L0/L1 references now not working

[RedDwarf]

I have been having problems with Hybrid for quite some time, at some point it stopped allowing me to select Multilevel L0/L1 References when using NVEnc. I have used this in the past, I cannot remember where it worked unfortunately. That was many many nVidia driver updates back.
The Multilevel L0/L1 tick box cannot be ticked or slider cannot be adjusted on either H264 or H265 encoding.

Has support for the Multilevel L0/L1 references been removed by nVidia?

Hybrid 2023.03.17.1 on Windows 10 x64
nVidia driver currently 537.13
GTX 1660 Turin Core supporting H.264/H.265 encoding