Hello Takayuki,
I’ve read your answer and have a following question:
I use reCAPTCHA v3 too and everything is ok. But why is this logo on the bottom right? I don’t have anything against the logo, but on the bottom right there is my PageUp-Button. Now I can’t see my PageUp-Button anymore. Is there a possibility to change the position of the reCAPTCHA-logo ???