Forms into content widget
Possible Answers to Your Question:
Yup. I’ve had the same issue with an Events Calendar form.
A way around this is to create a short code that contains your form’s HTML and insert it in your content widget. The content widget supports short codes and won’t strip it.
There are plugins that will let you create custom short codes for free. I’ve tried this: Insert Html Snippet and it worked great even though the plugin is a bit “clingy”—you’ll have to clean things a bit if you don’t want their branding on your site.