Problems with "Custom Contact Forms"

Hello, I am having a weird problem with “Custom Contact Forms”, I am creating a form and put it in a section called contact, left him well configured with their fields and all good, but every time I login to update page “Contact” where this the shortcode for this form, at the end of save, the form disappears, and I will see the form and what disappears are fields that were created; This happens to me over and over again, I think them fields and everything well, keep the page where this the shortcode and deleted fields…
I have created a form of zero again, and the thing remains the same, the new form is the same. Please, your help.

https://ww.wp.xz.cn/plugins/custom-contact-forms/