Hello Tomasz,
I have taken a look at your message. You are sending a message to Art-Net net:1, sub:0, universe:1. The QuadCore only supports net:0, sub:0-15, and universe 0-15. This is why the ART net indicators does not turn on. Because the QuadCore thinks this is a message intended for some other device.
Also it seems you have found a bug which we will have to solved. Because of this bug Art-Net messages with less then 512 channels get copied incorrectly. As a workaround you could use an Art-Net message with 512 channels. I am not very familiar with the Crestron system. Is it possible for you to send 512 channels?
Best regards,
Guido