I’ve found !!!!! thanks
Very strange…
It seems that, in my fieldgroup, a new invisible et anonyme textfield has been created (maybe during the update, maybe by a different user of the admin…). This field seems to clear post title each time I update my posts…
So I really don’t know if it was a bug or a misuse of my myself or another user, but it works 🙂
If I meet another time this problem, I will give you more informations, for now it seems solved 🙂
and a big thank for this very useful plugin !