nova-flexible-content: JS error: TypeError: Cannot read property 'status' of undefined

Previously we were getting this error (https://github.com/whitecube/nova-flexible-content/issues/55), so I decided to update from 0.1.7 to 0.1.9. That error is gone, but now I’m getting a completely different error when trying to create/update. The create/update button won’t let me submit. Here’s the JS error:

TypeError: Cannot read property 'status' of undefined
    at p.<anonymous> (app.js?id=b8265367338097693595:formatted:13231)
    at y (app.js?id=b8265367338097693595:formatted:16860)
    at Generator._invoke (app.js?id=b8265367338097693595:formatted:16838)
    at Generator.e.<computed> [as next] (app.js?id=b8265367338097693595:formatted:16875)
    at o (app.js?id=b8265367338097693595:formatted:22898)
    at app.js?id=b8265367338097693595:formatted:22910
    at new Promise (<anonymous>)
    at new t (app.js?id=b8265367338097693595:formatted:25246)
    at p.<anonymous> (app.js?id=b8265367338097693595:formatted:22895)
    at p.<anonymous> (app.js?id=b8265367338097693595:formatted:13239)
It @ vendor.js?id=da751a53228a35fab7c4:formatted:39444

The culprit might be R64’s Nova Fields again (if that’s the case, I’ll open a ticket with them), but we need to wrap Flexible content and a few other fields in this R64 JSON field for our data needs:

            JSON::make('Details', [
                Text::make('Test', 'test'),
                Text::make('Test 2', 'test2'),
                Flexible::make('Student Choice Selections', config('magento.gp_bundle_student_choices'))
                    ->button('Add Student Choice Item')
                    ->addLayout('Student Choice Selections', 'student_choice_selections', [
                        Text::make('Choice Description', config('magento.gp_bundle_student_products.selection_title'))
                            ->fieldClasses('choice-description-field px-8 py-6')
                            ->rules('required'),
               Text::make('Test 3', 'test3'),
               Text::make('Test 4', 'test4'), 
            ], 'data')->fieldClasses('w-full')
                ->labelClasses('w-1/6 px-8 py-6 hidden')
                ->hideFromIndex(),

Wrapping it with another Flexible field instead of this JSON field isn’t going to work for us.