when I send midi out on channel 2, and device one, I can receive it. But it will not work when I do the same, but with device 2... Bug? Glitch? Fixable?

The channel arguments for MIDI objects in Pd are (device number - 1) * 16 + channel number. In other words, device 1 is channels 1-16, device 2 is 17-32, etc. So channel 2 on device 1 would be [noteout 2], whereas channel 2 on device 2 would be [noteout 19].