Search Field on Safari Randomly not Responding

Sometimes when I search something on my iMac, and I enter the text in the field "search or enter website name", after clicking return, nothing happens. Or the text goes back empty. I do that several times and nothing happens.

Same thing if, in these occasions, I enter any website name. It's like dead.

Even if I restart Safari, things don't change. I have to restart the computer to make it work again.

Do you know why is this situation happening? Is there anything I can do to check for any problem?

Thanks