Having received a Pi 4B today with all the bits to make a system, I let it
install and update the OS. A bit later I shut it down, and then turned off the
Pi power supply.

The Pi carried on being powered. After dismissing the possibility of sentient
self-powered computers taking over, I discovered that the volts were coming
via the HDMI port.

Why is this? Is it normal? Is it safe? Anything special I need to do on
shutting down?

Plugging the HDMI cable back in and restoring normal power and all appears
fine But I'd like to be sure to avoid damage.

The HDMI cable is connected to one of these:



which is quite handy to allow two screens on the Mac and then switch one to
the Pi.

--
Tim

--- SoupGate-Win32 v1.05