3 times confirm e-mail, why?

Typically when a form creates duplicate entries or sends multiple notifications it is due to a theme or plugin conflict causing the form to submit multiple times. We have seen this happen with the Headspace plugin, although it comes and goes as the Headspace developer changes his plugin. Not sure what he is doing sometimes...

But I would first check for theme and plugin conflicts. To do so you need to activate the default theme and then test that form. If it works then there is a theme conflict, probably something in your functions.php file that is causing a conflict with the form submission.

If it's not the theme then you need to test plugins by deactivating them all and then activate only Gravity Forms. Then activate each plugin one by one, and test the form that is sending multiple notifications after each one until you determine if a plugin is causing the issue to occur.

What you can do is try contacting the developer of that plugin and explain the issue. It's most likely outputting Javascript when it should not be. It's pretty common for developers to globally output code. This means that they output javascript to the page even when it is not necessary. When you do this, it can case conflicts with other plugins. This is how most conflicts with Gravity Forms occur. A javascript error happens because of this and then it causes javascript to quit executing, and the form builder won't work at that point if javascript stops executing.