On the BTCC we don't see the beet taking energy on the dash! I think that the energy recovery works but you can't see it in "Bat level" on the dash!
it was on an LFM race so 2022 I think! The energy recovery was working well but it wasn't written on the dash in "bat level" https://www.twitch.tv/videos/1758435899
I've had it happen to me too. Everything is working fine and then later in the race, I noticed that the battery level was low - < 30% and then noticed that it wasn't recharging when braking like it had before. This was in an online race with the 2022 cars. I've not used the cars much since, so haven't seen it again.
I did 2 more races with the same bug, the battery gauge of the dash does not increase during braking...
I wonder if anyone has got it down to 0% and what happens then. I assume it would not allow hybrid deployment at that point.