System.conf FreePBX

Hello, FreePBX distro has a bug when configuring the Dahdi System?

At the interface, when I try to put the parameter

dynamic=ethmf,p4p1/04:74:A1:00:05:55/0,31,0

and below the

dynamic=ethmf,p4p1/04:74:A1:00:05:55/1,31,0 it overwrites the system.conf, showing only one dynamic.

this is a bug or am I’m doing wrong?

Thanks!