Nintex form - Incorrect validation rule making Attachments disappear (or overwritten).

I had an interesting issue raised today by one of the customers I deal with regularly and thought I would share here.

Why is the attachments added to the list via the nintex form being removed or over written?

After wracking my brain (and google) I did not find an answer.

Taking a step I went through the form validation rules I found two of them had been incorrectly configured (using the isNullOrEmpty Runtime Function).

Once correcting the validation rule, the attachments stayed in the form / list.

isNullOrEmpty(Title)

I hope this helps others out there who are struggling with this.