This isn't true anymore, since modern laser projectors does not work like old light bulb driven projectors.
Most Panasonic laser projectors are dimable. In fact, instead of using a mechanical shutter, those modern projectors just shut down the light source to 'mute' the picture.
I don't really have a solution for your specific issue. But I would guess, it is something about the ArtNet "ENABLE/DISABLE" function. It seams to interfere with other remote controls. You should try to reset it, by disable (ArtNet default Channel 11 value to 1 and back to 255) before trying other settings. And try to always keep sending the "ENABLE/DISABLE" Value of 255.