Dell XPS 9300 + bios 1.9.1 = doesn't charge, fans try to turn into helicopters

Tried the 1.9.1 bios update for the Dell XPS 2020 9300 (Developer Edition model that was sold with Ubuntu 18.04).

First problem : you plug the USB-C plug and... laptop does not charge. You have to turn off the laptop. Then unplug and plug again the USB-C connector... or the laptop will not charge. Once the laptop has started, removing the power cable means you can no longer charge it unless you totally turn it off again.

Second problem : fans start going very loud and helicopter loud with no serious load on the laptop at all (unless a xterm opened full screen with nothing registers as high load with the 4 CPUs sitting under 1 % load).

Those 2 problems went away immediatly after installing the previous version of the bios (1.8.0) on the laptop. So this is not hardware related but BIOS related.

Is anyone at Dell aware of the bios 1.9.1 problems ? It's been well over a month and no update to the faulty BIOS is available.