"Batch assignment" will hide bugs in bugs list

I had 6 bugs in this project. #6 was assigned to user "davide" entering in its detail and then assigned, but other 5 are assigned to same user via "batch assign" clicking on "gear icon".

As you can see, in top pane is indicated that there are 6 "Confermato" bugs but below I see only one of them. Writing dirtecly others bugs url, I can see them so they correcly are stored in DB.