BTT Pi v1.2 very odd USB behaviour.

[Bunik]

Hello,
I just received Btt Pi v1.2 and hooked it up with Octopus Pro and U2C.
Now the problems.
BTT Pi communicates with Octopus pro ony with the original USB C cable that came with the Octopus. Any other C cable I have got does not work and lsusb does not show anything.
U2C does not appear on the list even with that cable. I cannot see it.
When connecting one device at the time.
I also tried to hook up the SB2209 / SBB2240 so I can update the firmware. It does not see it and it does not light the ligts on it.
Even when using the same cable as for the Octobus.
Trying other three USB 2.0 slots does not help.

Now the fun part. I used any other cable with the U2C, or the SB2209 and it works with my laptop. Windows immedietely sees the device and I can even put them to DFU mode. All LEDs on both devices also light up correctly.

It looks like a fault of the Pi, but I have no idea how to resolve it. If it is even possible.
Thanks in advance for any advice!

[Bunik]

Update:
I have been testing this further and sometimes, just sometimes the U2C lit up when I turned on power to the BTT Pi.
After unplugging and plugging it in again to turn it to DFU mode it did not light up again.
Turning on/off the PI sometimes helped, sometimes the U2C just flashed diodes for a second.
I wondered if there is something with the 5V line. So I disconnected the Sunon 5V 0.38W (MF25100V2-1000U-A99) fan which did not work on the PI anyway (It works on the Octopus 5V fan though)
And suddenly all the problems went away? Now I can use all the cables to connect to all the devices at the same time and they stay on even when I re-connect them.

So I plugged the fan in again to reproduce the issue. I cannot reproduce it again. The fan is still off though.

I am baffled what is going on with this. I will keep testing this board later when I full configure Klipper on it to see how it behaves with a heavy load. I will probably have to wire the 5V fan somewhere else to keep the board cool, which is a bit annoying.