What do you mean by “headless platform” ? Could this help ? If you could gain access on a terminal (telnet or ssh) to your platform then may be you could start DeCONZ in debug mode to have some log ? But it’s perhaps overkill for the moment.
Without further information it will be difficult to troubleshoot because there could be a lot of source, beginning by the device themselves … have they the same firmware that the one that give the DDF to be developped ? Or may be that the DDF you mention is not already on your system, depending of your Deconz version.
What do you really mean by the DDF “is well available on my system and it seems that the config does mention the consumption.” ? From where is the consumption absent ? The DDF on your system ? The sensor JSON from Phoscon ? …