MacBook Pro M3 battery completely drained even when connected to USB-C

Well. I was working with my MacBook M3 connected via USB-C to an external display (and charging) when suddenly it completely shut down. It turns out that, while still connected to the display and receiving power, the battery has completely drained! (I have to say that at the time I did not have any applications running that used too much energy)

How can this be!!?? I find it shameful that something like this is happening with such an expensive device, I understand the optimisation of charging to extend battery life, but this?