first issue sends ok second just to user

Hello,
I did an in-depth look at the plugin since sending a notification to the user and the administrator is only sent once and then opening a new issue only the notification is sent to the user.
I tried turning off all the plugins and switched to a Twentysixteen theme but got the same result.
So I opened a demo site free of any plugins and still get the same result
The first issue sends to the administrator and user as expected and the second issue only to the user.