I wonder...

Regenerative braking is INSTANTLY disabled when/if ABS activates during actual (hydraulic) braking. I wonder if maybe it isn't subsequently re-enabled unless there is a follow on forward motion via throttle opening. Assuming you shut the ignition off immediately after ABS's activation it may have remained "off' until the restart the next morning.

The kind/type, not readily foreseeable, of firmware bug that can be easily over-looked.

Look at:

U0100, U0111

A "quick" ignition shutdown might prevent the follow-on "regen" re-enable "message". Or the "re-enable" of regen was/is a function of forward motion under power subsequent to an ABS disable.

If regen were to be disabled due to ABS activity I certainly would not want it to be re-enabled, say during a follow-on coastdown, non-braking coastdown, to a full stop.