Pin behaviour at start up

[Jonathan2892]

Hi,

I have 2 esp32-s3-wroom-1-n18r8 modules. I am using GPIO11 as output and the pin is connected to ground via 20k pull-down resistor. Nothing else is connected.
According to the technical reference this pin should be floating at start up, thus GPIO11 should be LOW on start up. This is indeed true for one module, but on the other module I measure some pulse. I also measured GPIO3, as this pin should have the same behaviour as GPIO11 and it shows exactly the same behaviour.
You can see the pulse on the wrong working module in the picture.

IMG_5105.jpeg (2.82 MiB) Viewed 839 times

Can anyone explain this behaviour? I do not think that the esp32-s3-module is broken, since I can upload firmware and it is running okay.

Best