There is no line in translate.c that would produce output like that, let alone one near line 597, in either Asterisk 16.1 or 16.15. It seems unlikely that any other sub-version of Asterisk 16 would include it.
I’m not sure if FreePBX modifies the source (this isn’t a FreePBX forum), but, otherwise, you will need to ask whoever ported it to armhf.
In addition, chan_dongle is not part of Asterisk, not even as community supported code. Support is reportedly provided at http://groups.google.com/group/chan_dongle