On my form a I have a product field that is required. The first value is blank, however the form is able to be submitted using the blank option. Using the GF logs I’ve noticed the value for the blank field is “|0” (a price of $0).
I believe this may be a bug, as this is an old problem per this thread from the legacy forums: Gravity Support Forums
Hello. Those old forum posts are out of date. Please remove the blank first option, and add a Placeholder on the Appearance tab. That will ensure that someone makes a product selection in your required field.
If you have any other questions, please let us know.