Excel Import not adding row to database

Hi - I'm hitting a weird problem using Maatwebsite Import. This is a great product, so I'm sure I've got something wrong. I'm importing a csv file with 12 columns. In my sample, only four of the columns have data:

title	subtitle	arrangement	artist	composer	arranger	lyricist	choreographer	words and music	file locator 1	file locator 2	file locator 3
A Chorus Line		SATB	Harry Simeone						A	2	
Achieved Is The Glorious Work		SATB	Franz Joseph Haydn						A	3	
Adam Lay Ybounden		SATB	Boris Ord						A	4	
Adoramus Te		SATB	Palestrina						A	5	
Adoramus Te		SATB	Quirino Gasparini						A	6	

When I test a "title" insert on Tinker, it works as expected. When I run the Insert, it appears that rows are being inserted, but in fact, there is no row in the database.

> $t = \App\Models\Title::firstOrCreate(['title' => 'A Chorus Line', 'alpha' => 'Chorus Line, A'])
= App\Models\Title {#7327
    title: "A Chorus Line",
    alpha: "Chorus Line, A",
    updated_at: "2023-10-28 09:52:01",
    created_at: "2023-10-28 09:52:01",
    id: 30,
  }

However, when I run the Import:

<?php

namespace App\Imports;

use App\Models\Teachers\Schools\Libraries\Items\ArrangementType;
use App\Models\Teachers\Schools\Libraries\Items\Subtitle;
use App\Models\Teachers\Schools\Libraries\Items\Title;
use Illuminate\Support\Collection;
use App\Models\Teachers\Schools\Libraries\Items\Item;
use Illuminate\Support\Str;
use Maatwebsite\Excel\Concerns\OnEachRow;
use Maatwebsite\Excel\Row;

class ItemsImport implements OnEachRow
{

    /**
     * Row columns are expected to be in this order:
     * 0 => title
     * 1 => subtitle
     * 2 => arrangement
     * 3 => artist
     * 4 => composer
     * 5 => arranger
     * 6 => lyricist
     * 7 => choreographer
     * 8 => words and music
     * 9 => file locator 1
     * 10 => file locator 2
     * 11 => file locator 3
     */
    public function onRow(Row $row)
    {
        $item = new Item;

        $rowIndex = $row->getIndex();
        $rowData = $row->toArray();

        if (strlen($rowData[0]) && (strtolower(trim($rowData[0])) !== 'title')) {

            $title = Title::firstOrCreate([
                'title' => $rowData[0],
                'alpha' => $rowData[0],
            ]);

            $subtitle = ($rowData[1]) ? Subtitle::firstOrCreate(['subtitle' => $rowData[1]]) : new Subtitle;

            $arrangement = ArrangementType::firstOrCreate(['descr' => $rowData[2]]);

            dd($title);
        }
    }

the dd($title) responds:

App\Models\Teachers\Schools\Libraries\Items\Title {#7269 ▼ // app\Imports\ItemsImport.php:51
  #connection: "mysql"
  #table: "titles"
  #primaryKey: "id"
  #keyType: "int"
  +incrementing: true
  #with: []
  #withCount: []
  +preventsLazyLoading: false
  #perPage: 15
  +exists: true
  +wasRecentlyCreated: true
  #escapeWhenCastingToString: false
  #attributes: array:5 [▼
    "title" => "A Chorus Line"
    "alpha" => "A Chorus Line"
    "updated_at" => "2023-10-28 09:43:38"
    "created_at" => "2023-10-28 09:43:38"
    "id" => 29
  ]
  #original: array:5 [▶]
  #changes: []
  #casts: []
  #classCastCache: []
  #attributeCastCache: []
  #dateFormat: null
  #appends: []
  #dispatchesEvents: []
  #observables: []
  #relations: []
  #touches: []
  +timestamps: true
  +usesUniqueIds: false
  #hidden: []
  #visible: []
  #fillable: array:2 [▶]
  #guarded: array:1 [▶]

but there is no id 29 created in the database! Here's the migration for the titles table, just in case:

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration {
    /**
     * Run the migrations.
     */
    public function up(): void
    {
        Schema::create('titles', function (Blueprint $table) {
            $table->id();
            $table->string('title', 120);
            $table->string('alpha', 120);
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     */
    public function down(): void
    {
        Schema::dropIfExists('titles');
    }
};

Thanks for any help you can offer!