An Update on the issue.
I have the questions group by group. Let´s say that on the first group, I have 2 array type questions, among others...
When I answer that first group, all of the answers from all of the questions are saved OK in the database.
Then I answer the 2nd group and when I go to the 3rd group (meaning that the 2nd group its being saved on the database), I loose the answers on the 1st group, starting from the 2nd array question to the end of the group.
I really don´t know what to do, It´s so weird, never happened to me before...
I´ve tried moving the survey to another server, removing the token-based persistance, making the survey anonymous, But so far, nothing has solved the issue.