[Plugin: Grunion Contact Form] Five field bug?

I feel like this should have come up before so if I am repeating something I apologize but I couldn’t find it referenced anywhere else.

I have a client that claimed that the amount of fields she was able to input was limited to a pretty small number. So I did some testing on a site that I have grunion installed and a site that is using jetpack. Both had the same result.

If I add five fields the “Add a new field” link disappears. If I save the form and then click the “add a custom form” button to edit it again I am able to add five more. If I repeat this I can essentially add as many as I want.

Why is the “Add a new field” link disappearing? Is it a bug or is there a reason.

Thanks in advanced.

http://wordpress.org/extend/plugins/grunion-contact-form/