Lionel, my apologies for being so vague. I just upgraded to Seblod 3.1.3., but the problem was occurring in 3.1.1.
I create a list directory that includes 1 image field, 4 text fields and 2 dropdowns. The second dropdown is a conditional statement of the first dropdown. I also create a frontend form and backend input form to add the new item. The form creates a new article assigned to a specific category (hidden field).
When I add the new article everything works fine. A few days later, some articles stop showing in the search results and it says "There is no result". When I open the article in the backend there is no form, just a normal article showing ::cck::113::/cck:: in the article editor (previously called custom output). I delete the article and add it back and everything works. The issues starts over again a few days later. Sometimes I open the Content Type and save it and some of the articles come back, but not all of them.
Hope this helps. Thanks in advance.