Unoconv does not output anything to stdout. What could be the reason?

Question

linux

opensuse 13.2
unoconv-0.6-6.4.1
Modules in node js that need unoconv suddenly stopped working. It looks like the reason is that nothing is being passed to stdout.
Nothing happens on the command:
unoconv --stdout -f html file.odt
without --stdout everything works as standard.