2.1.6 mautic
when user fills out the form and press send the notice appear about submission being succesful and then form empties and reapear again, it does not dissapear, in fact I have to press X to close it…
I have this issue too, and I am on version 3
confirmed this is present in 3.x as as @devsrealm mentioned. My workaround was to add a redirect on the form back to the home page, not ideal, but gets the job done.
I actually think this might be a focus item feature, that you need to X it to get it away. would be nice if you could also just hit anywhere on the page to make it go away
You can do that, or it works for me.
I was with a client yesterday and had a form popping up but had to X it to close, Mautic 3.x 
Mine is 3.0.1, I am using the Notification Style if that helps.