Nvsdk nvEncInvalidateRefFrames not works

Hi, Guys
It seems api nvEncInvalidateRefFrames does not work on my Quadro T1000 card.
It always returns zero with Whatever inputs.

Here is my HW&SW circumstance:
Quadro T1000
Win64+ NVSDK 11.1
Encodeing HEVC with UltraLowlatency preset

I found a previous post in. this forum

It seems some kind of platform do not support nvEncInvalidateRefFrames.
Anyone know in what nvsdk version or platform it works ?

Thanks.