Allready tried that too. The error persists, wether i run it from cli or through apache. No errors show up in the log, soffice just quietly exits with no error.
What I found on the document foundation bugtracker was this: https://bugs.documentfoundation.org/show_bug.cgi?id=37531
Although it should be fixed in the current version, my problem disappears if I set a random home directory for soffice. With removing the directory afterwards, ther is only a small impact on runtime. Maybe this helps you in some way.