I am inclined to agree with Skyking. I have two very similar FreePBX systems, both running identical Sangoma DAHDI hardware, both with the wanpipe driver. These systems were set up a year apart so there are minor differences between asterisk versions and OS versions, but the main difference is that one uses the FreePBX DAHDI config module, and the other does not. Comparing date stamps on the file /etc/wanpipe/wanpipe1.conf on the two systems, the PBX running the FreePBX DAHDI config module is dated two days ago, the most recent reboot. On thhe other system, the file is dated from the day a year ago when the TDM card was installed.
At the moment I can't confirm if changes to wanpipe1.conf persist between reboots, but can test after hours if requested. In any case, if this file is 'owned' by FreePBX, there is no header indicating as such, only the header generated by the Sangoma setup script:
Note: This file was generated automatically
by /usr/local/sbin/setup-sangoma program
Could there be something in the FreePBX DAHDI config module that forces the Sangoma setup to generate this file on every reboot?