DHCP Leases Bridge port: Unknown

A few days ago it showed the interface the device is connected to. But now:
Untitled.jpg
What could I have done wrong?

Perfect solution for you:

http://forum.mikrotik.com/t/getting-the-most-out-of-this-forum/40983/1

Did you found a solution? I’ve the same issue.
The unknown-status occurs only on the wifi-wave2-2g interface but not on wifi-wave2-5g although they’ve identical configuration (except ghz).
Both interfaces are assigned to the same port of bridge_lan, nevertheless the Bridge-port in the leases is unknown only for 2g.
Also reset of the interfaces did not lead to success.

Any hint would be appreciated