Issue
After updating to Nintex Forms 2013 build 2.9.3.0, the default value for the Single Line of Text Control has changed from "0", when using integer data type on the control settings, to null.
Resolution
This is by design. Update the default value control settings for the Single of Text controls used in your form to "0" to avoid the field being set to null.
Additional Information
See the Nintex Forms 2013 release notes for information regarding the change.
