I’m sorry @sbouey, perhaps I expressed myself wrong.
I installed Falang for Elementor Lite with Falang, not Polylang. What happened is that I uninstalled Falang to test Polylang later, so I selected to remove Falang data at uninstall.
Right after remove Falang the problem appears, I’m sorry, but I needed to get the site back fast and couldn’t debug exactly what happened but all elementor data in posts have gone at that moment. The posts have not been deleted but the elementor data (widgets used, models types and so on)