Nvidia-SMI, encoder.stats.sessionCount always reporting 0


I’m trying to use nvidia-smi to check how many (HW) encoder sessions I have running, to avoid crossing the maximum limit => switch to SW encoding if needed. But, when I run,

sudo nvidia-smi --query-gpu=encoder.stats.sessionCount --format=csv,noheader -i 0

the result is always 0, even if I have HW encoding sessions running. Is this a known issue, and is there a workaround?