File Attachment doesn’t work if the CF is opened in-app (e.g. Facebook App)

Hello.

I’m not sure if I’m the only one experiencing this weird issue.

The contact forms work perfectly everywhere, except the file attachment feature when opened in-app.

For example: let’s say I have a contact form on a page in which I have a required attachment field. I share this page on Facebook. When people click on the Facebook post, the page is opened (by default?) in the app and not in the browser.

In this specific case, users can’t upload any file. Every other field works fine. File attachement doesn’t.

What am I missing? Is this something related to the plugin or it’s my fault?

Thank you in advance.