Alexander, just confirming that this behavior is consistent.
On the initial recognition, it is assigned ttyACM0, but NetworkManager can't use it (I don't know why not). After removing the device, and even if removing /dev/ttyACM0, reinserting the device it gets /dev/ttyACM1, which NetworkManager doesn't want to use. Creating the symlink makes it work.
So we have a workaround, but also a reproducible situation that should be fixed.
Alexander, just confirming that this behavior is consistent.
On the initial recognition, it is assigned ttyACM0, but NetworkManager can't use it (I don't know why not). After removing the device, and even if removing /dev/ttyACM0, reinserting the device it gets /dev/ttyACM1, which NetworkManager doesn't want to use. Creating the symlink makes it work.
So we have a workaround, but also a reproducible situation that should be fixed.