Did you add code on the ZC that also makes a similar call to ZDP_EndDeviceBindReq() when a new device joins? Even when you get this working, what are you going to do when the ZC is 4 hops away from the ZR device that the ZED device joins and the ZC misses the device announce? Obviously, a more sophisticated method of "network commissiong" needs to be developed for your product. There is a ton of dicussion that you can search for on this topic.