Tahoe 26.4: Screen brightness increasing without user intervention

Hi all,

Am noticing odd behaviour on my MacBook Pro running Tahoe 26.4. I keep my screen brightness at 0%, however I am noticing several distinct anomalies:

1. Sometimes when I press FN-F1, Vo reports screen brightness at 6% after the first key-press, then 0% thereafter. or
2. Screen brightness seems to auto-increase to 35-40%, without any intervention from me.

In other words: it does not remain at the 0% value at which I set it. Anyone else encountered this? Nothing is showing in System Settings which suggests an issue there.