yasnippet losing default snippets

[andrea]

A strange thing happened, now yasnippet is only loading my personal
snippets and not anymore the defaults one.
My configuration is pretty simple

--8<---------------cut here---------------start------------->8---
(require 'yasnippet)

(setq yas/root-directory
      '("~/.emacs.d/my-snippets/text-mode/"
        "~/.emacs.d/yasnippet/snippets/"))

;; Maybe needed to set to fixed for some modes
(setq yas/indent-line 'auto)

(yas/initialize)

(setq yas/ignore-filenames-as-triggers t)

(mapc 'yas/load-directory yas/root-directory)

;; don't make backups in the snippet folder, they mess up yasnippet
;; Should this really go here?
(add-to-list 'backup-directory-alist '("/my-snippets/" . "/tmp/"))
--8<---------------cut here---------------end--------------->8---

and it always worked.
I can see the snippets loaded from the menu and if I click on them they
work, but if I try to expand the right keys it doesn't find any
completion.

I also tried to load only subdirectories for modes (maybe I modified
something) but it's the same, and I don't get any error message.
What could that be?