Text of Ninja Form shows up on non-form widgets

Hello, something very odd has happened since update.

I find that pages which contain a ninja form, also show up in the side bar widget as pure text.

For instance, my sidebar has a Category Posts Plugin widget to display all posts of a certain category. This widget is on my Contact page which has a ninja form on the main content area. All the form fields of the ninja form, such as name, email etc show up in my category widget!

I tried activating and reactivating, but still problem.

Hope someone can advise? Thank you.

https://wordpress.org/plugins/ninja-forms/