There seems to be a bug in the way, doctrine tries to find a unique slug for a table that is I18N-enabled and has a slug in it.
Now, if we insert a new entry, the slug get's created as expected. If we now insert another entry that would yield the same slug, the slug is made unique by adding the postfix as expected - all well so far.
Now, if we try to update the entry with the slug with the postfix, what i think is an error happens (Excerpt from Sluggable.php, lib/Doctrine/Template/Listener/Sluggable.php):
So, the $record->exists() check evaluates to true and $table->getIdentifierColumnNames() yields the fields id and lang, so the whereString is something like
Now for the problematic part:
uniqueBy is lang and name; so the code adds to the whereString:
So the resulting whereString has something like
which will never yield a result in my eyes, thus, the postfix is never incremented and the slug defaults to the the slug of name without postfix.