CF7 don’t save changes

On all the forms of my site, I have the following problem: after having modified and saved one of my forms, I return to the dashboard of wordpress to continue working. At this point, Contactform7 displays an alert window to indicate that the changes will not be saved ???
When I click Exit and then come back to my form, I notice that the changes have been saved.
Then yesterday, I had a more serious problem, a lot of my changes were not saved and I lost a day of work! Can you explain to me what’s going on, it’s incomprehensible!