ETA: Also posted as Github issue #1272.
ESS schedules are not updated when Venus transitions to daylight savings. @tpbradley filed this same bug last year, but they noted here that Venus v2.93 fixed a bug requiring a reboot after changing timezones, and hoped that it might have been fixed in that release.
It's unclear from the changelog whether that fix applies only to manual changes of base timezone, or whether it includes DST changes, too.
In either event, v3.14 exhibits the same behaviour. Timezone is set to Europe/London rather than UTC, and I've verified via remote console that Venus does reflect the correct BST time. DST transitioned happened at 2am on Sunday 31 March 2024 so this (contracted) screenshot shows the beginning of scheduled charge at midnight on the morning of the 31st to the beginning of scheduled charge on the following day:
Note that on the Monday, charging began at 1am, ie midnight UTC instead of midnight localtime.