hi to all, running c8.10

When I launch single automated jobs the "Index Search Engine - All" returns ...nothing, whereas the site has more than 200 pages and the job "Index Search Engine - Updates" seems to work correctly (see attached)

How can i fix it ?
should I clear some table ?

I have to work out because it seems that the search feature is fine but only for new changes, not the initial site contents

Tahnk you all for help