Filament Select with searchable(): value is null on Create but works on Edit (JSON/dot-path field)

I’m seeing an odd mismatch with Filament v3 Select + searchable(): when the field is bound to a JSON key using dot notation (e.g., properties.business_field_id), the value does not dehydrate on Create (ends up null in DB), but works correctly on Edit. Other JSON-backed fields on the same form save fine on Create; only the searchable Select fails.