two instances of the same device, second doesn´t work.

Hi,
i have a device which grabs the buttonmatrix of the Push2, there are no send/receive in the patch, at this point the device is only grabbing and releasing the matrix on track change (live.object and observer). it works fine but once i open a second device in another track the first one stops working and won´t access the matrix anymore.

i would be thankful for any idea why this happens.