Ninjaform connect to give category?

We are moving this from Caldera Forms.
First we used the Caldera to Ninjaforms converter and that brought over the basic fields.
Then I used their Front End Posting to connect to Give, along with putting in the special meta keys seen in JSM Custom Meta into the form.

But that didn’t show any meta field for Categories. So I compared the old Caldera Form and sure enough that did have one. give_forms_category on the ‘select your event’ dropdown.

But adding in that meta key does not work. All my other fields are mapped on my demo and correctly posting from NinjaForm to give. It’s ONLY the category that isn’t mapping. What am I missing please? I’m on a demo now so I know all the steps before I do the live ones.