Error configure a Y416 HEVC encoder

[cedronius__anders]

System : Ubuntu 20.04

CPU:

model name : Intel(R) Core(TM) i5-10210U CPU @ 1.60GHz

libva:

libva info: VA-API version 1.11.0
libva info: User environment variable requested driver 'iHD'
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so
libva info: Found init function __vaDriverInit_1_11
libva info: va_openDriver() returns 0

MSDK:

Notification: The MSDK version Loaded is: v1.35

When trying to encode Y416 frames I get the error unsupported

Results in ->

Forcing the code/encoder to encode P010 frames generates no errors >

Results in ->

Why?

Thanks for helping.

/Anders.