We have found that the Crestron C2N-IIF v5.1 modules don't always function correctly when in large systems. The module was trying to send it's information almost immediately at bootup. We have modified some of the timing in their Simpl+ module to make it more reliable for us.
Open C2N-IIF Simpl+ v5.1.usp and replace lines 46-57 with the following lines and recompile.
delay(500); delay(sr * 50); //wait different times depending on room number //{ if(len(DSRoute$) > 4) //don't send empty string { to_room_mod$ = DSRoute$ + "\xE1"; //send this ds routes to other modules } //}