Error from MariaDB SQLSTATE[HY000]: General error: 1364 Field doesn't have a default value

I have a form submitting a bunch of data. I seem to have all the values printed when I dd($request). But when I make an actual submission to the database, I get an Illuminate\Database\QueryException that tellsme one of the fields has no default value.

I am using Actions and Custom form Requests:

// This is in my rules() function

return [
	'name' => ['required', 'string'],
	'email' => ['email', 'nullable', 'unique:patients,email'],
	'gender' => ['required'],
	'age_type' => ['required'],
	'age' => ['required', 'numeric'],
	'dob' => ['required'],
	'address' => ['required'],
	'occupation' => ['required'],
	'mobile_number' => ['required'],
	'nok_id' => ['required'],
	'relation_to_next_of_kin' => ['required'],
	'other_relation_to_next_of_kin' => ['required_if:relation_to_next_of_kin,5'],
	'referral_point' => ['required'],
	'referral_point_details' => ['required_if:referral_point,2,4,5'],
	'other_referral_point_details' => ['required_if:referral_point,2,4,5'],
	'insurance_scheme' => ['required'],
	'insurance_id' => ['required_if:insurance_scheme,1'],
	'insurance_number' => ['required_if:insurance_scheme,1'],
	'date_recorded' => ['nullable', 'date'],
];

// I use a simple action in my controller's store() function:
CreatePatient::execute($request->validated());

But it tells me the Field relation_to_next_of_kin doesn't have a default value. I don't know what the problem is. When I dump the data, I get the value passed for that field.