slave reacts to two different masters

[nettings]

On the master:
medianet@mn-vpknobs:/medianet $ gpioctl -r 12,16,master,osc.udp://239.0.0.10:3042,1 -s 26,master,osc.udp://239.0.0.10:3042 -r 8,7,master,osc.udp://239.0.0.200:3042,1 -s 25,master,osc.udp://239.0.0.200:3042 -r 23,24,master,osc.udp://239.0.0.253:3042,1 -s 22,master,osc.udp://239.0.0.253:3042 -r 27,17,master,osc.udp://239.0.0.1:3042,1 -s 13,master,osc.udp://239.0.0.1:3042 -v
ROTARY 12 -> MASTER 1
ROTARY 12 -> MASTER 1
ROTARY 12 -> MASTER 1
ROTARY 12 -> MASTER 1
ROTARY 8 -> MASTER 1
ROTARY 8 -> MASTER 1
ROTARY 8 -> MASTER 1
ROTARY 8 -> MASTER 1
ROTARY 8 -> MASTER 1
ROTARY 23 -> MASTER 1
ROTARY 23 -> MASTER 1
ROTARY 23 -> MASTER 1
ROTARY 23 -> MASTER 1
ROTARY 23 -> MASTER 1
ROTARY 23 -> MASTER 1
ROTARY 23 -> MASTER 1

On the slave, the first rotary (12 above) is ignored (correct!), but then the slave follows both 8 and 23:
medianet@mn-mediacenter:~ FS WRITABLE $ gpioctl -U osc.udp://239.0.0.253:3042 -R PCM -S PCM -r 5,6,master,osc.udp://239.0.0.253:3042,1 -s 13,master,osc.udp://239.0.0.253:3042 -v
ROTARY 64 -> SLAVE -9
ROTARY 64 -> SLAVE -8
ROTARY 64 -> SLAVE -7
ROTARY 64 -> SLAVE -6
ROTARY 64 -> SLAVE -5
ROTARY 64 -> SLAVE -4
ROTARY 64 -> SLAVE -3
ROTARY 64 -> SLAVE -2
ROTARY 64 -> SLAVE -1
ROTARY 64 -> SLAVE 0