Running php artisan scout:import or php artisan scout:reimport on a Pivot Model (Illuminate\Database\Eloquent\Relations\Pivot) that implements shouldBeSearchable() generates an Exception because Illuminate/Database/Eloquent/Relations/Concerns/AsPivot.php::newQueryForCollectionRestoration (289) requires an array starting with $ids[0] and shouldBeSearchable() after filtering gives an array starting with an index greater than zero.

I've created an fresh Laravel app with 3 models Company, Product and CompanyProductPivot + Scout with Algolia in order to reproduce the error.
storage/logs/laravel.log.git clone https://github.com/cstriuli/bug-scout-import
cd bug-scout-import
composer install
cp .env.example .env
php artisan key:generate
// update manually your Algolia keys and DB credentials
php artisan migrate --seed
php artisan queue:work
php artisan scout:import // or scout:reimport
open storage/logs/laravel.log
[2020-11-13 06:41:37] local.ERROR: Undefined offset: 0 {"exception":"[object] (ErrorException(code: 0): Undefined offset: 0 at /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Relations/Concerns/AsPivot.php:289)
[stacktrace]
#0 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Relations/Concerns/AsPivot.php(289): Illuminate\\Foundation\\Bootstrap\\HandleExceptions->handleError(8, 'Undefined offse...', '/Users/admin/Si...', 289, Array)
#1 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Relations/Concerns/AsPivot.php(267): Illuminate\\Database\\Eloquent\\Relations\\Pivot->newQueryForCollectionRestoration(Array)
#2 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/SerializesAndRestoresModelIdentifiers.php(114): Illuminate\\Database\\Eloquent\\Relations\\Pivot->newQueryForRestoration(Array)
#3 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/SerializesAndRestoresModelIdentifiers.php(73): Laravel\\Scout\\Jobs\\MakeSearchable->getQueryForModelRestoration(Object(App\\Models\\CompanyProductPivot), Array)
#4 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/SerializesAndRestoresModelIdentifiers.php(56): Laravel\\Scout\\Jobs\\MakeSearchable->restoreCollection(Object(Illuminate\\Contracts\\Database\\ModelIdentifier))
#5 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/SerializesModels.php(122): Laravel\\Scout\\Jobs\\MakeSearchable->getRestoredPropertyValue(Object(Illuminate\\Contracts\\Database\\ModelIdentifier))
#6 [internal function]: Laravel\\Scout\\Jobs\\MakeSearchable->__unserialize(Array)
#7 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/CallQueuedHandler.php(193): unserialize('O:33:\"Laravel\\\\S...')
#8 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/Jobs/Job.php(213): Illuminate\\Queue\\CallQueuedHandler->failed(Array, Object(ErrorException), 'ee250289-55a4-4...')
#9 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/Jobs/Job.php(192): Illuminate\\Queue\\Jobs\\Job->failed(Object(ErrorException))
#10 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(544): Illuminate\\Queue\\Jobs\\Job->fail(Object(ErrorException))
#11 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(505): Illuminate\\Queue\\Worker->failJob(Object(Illuminate\\Queue\\Jobs\\DatabaseJob), Object(ErrorException))
#12 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(433): Illuminate\\Queue\\Worker->markJobAsFailedIfWillExceedMaxAttempts('database', Object(Illuminate\\Queue\\Jobs\\DatabaseJob), 1, Object(ErrorException))
#13 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(410): Illuminate\\Queue\\Worker->handleJobException('database', Object(Illuminate\\Queue\\Jobs\\DatabaseJob), Object(Illuminate\\Queue\\WorkerOptions), Object(ErrorException))
#14 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(356): Illuminate\\Queue\\Worker->process('database', Object(Illuminate\\Queue\\Jobs\\DatabaseJob), Object(Illuminate\\Queue\\WorkerOptions))
#15 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/Worker.php(158): Illuminate\\Queue\\Worker->runJob(Object(Illuminate\\Queue\\Jobs\\DatabaseJob), 'database', Object(Illuminate\\Queue\\WorkerOptions))
#16 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/Console/WorkCommand.php(116): Illuminate\\Queue\\Worker->daemon('database', 'default', Object(Illuminate\\Queue\\WorkerOptions))
#17 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Queue/Console/WorkCommand.php(100): Illuminate\\Queue\\Console\\WorkCommand->runWorker('database', 'default')
#18 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(36): Illuminate\\Queue\\Console\\WorkCommand->handle()
#19 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Container/Util.php(40): Illuminate\\Container\\BoundMethod::Illuminate\\Container\\{closure}()
#20 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(93): Illuminate\\Container\\Util::unwrapIfClosure(Object(Closure))
#21 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(37): Illuminate\\Container\\BoundMethod::callBoundMethod(Object(Illuminate\\Foundation\\Application), Array, Object(Closure))
#22 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Container/Container.php(596): Illuminate\\Container\\BoundMethod::call(Object(Illuminate\\Foundation\\Application), Array, Array, NULL)
#23 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Console/Command.php(136): Illuminate\\Container\\Container->call(Array)
#24 /Users/admin/Sites/bug-scout-import/vendor/symfony/console/Command/Command.php(258): Illuminate\\Console\\Command->execute(Object(Symfony\\Component\\Console\\Input\\ArgvInput), Object(Illuminate\\Console\\OutputStyle))
#25 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Console/Command.php(121): Symfony\\Component\\Console\\Command\\Command->run(Object(Symfony\\Component\\Console\\Input\\ArgvInput), Object(Illuminate\\Console\\OutputStyle))
#26 /Users/admin/Sites/bug-scout-import/vendor/symfony/console/Application.php(920): Illuminate\\Console\\Command->run(Object(Symfony\\Component\\Console\\Input\\ArgvInput), Object(Symfony\\Component\\Console\\Output\\ConsoleOutput))
#27 /Users/admin/Sites/bug-scout-import/vendor/symfony/console/Application.php(266): Symfony\\Component\\Console\\Application->doRunCommand(Object(Illuminate\\Queue\\Console\\WorkCommand), Object(Symfony\\Component\\Console\\Input\\ArgvInput), Object(Symfony\\Component\\Console\\Output\\ConsoleOutput))
#28 /Users/admin/Sites/bug-scout-import/vendor/symfony/console/Application.php(142): Symfony\\Component\\Console\\Application->doRun(Object(Symfony\\Component\\Console\\Input\\ArgvInput), Object(Symfony\\Component\\Console\\Output\\ConsoleOutput))
#29 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Console/Application.php(93): Symfony\\Component\\Console\\Application->run(Object(Symfony\\Component\\Console\\Input\\ArgvInput), Object(Symfony\\Component\\Console\\Output\\ConsoleOutput))
#30 /Users/admin/Sites/bug-scout-import/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php(129): Illuminate\\Console\\Application->run(Object(Symfony\\Component\\Console\\Input\\ArgvInput), Object(Symfony\\Component\\Console\\Output\\ConsoleOutput))
#31 /Users/admin/Sites/bug-scout-import/artisan(37): Illuminate\\Foundation\\Console\\Kernel->handle(Object(Symfony\\Component\\Console\\Input\\ArgvInput), Object(Symfony\\Component\\Console\\Output\\ConsoleOutput))
#32 {main}
"}

artisan scout:import (without shouldBeSearchable/filtering):
Thanks, I've sent in a PR here: https://github.com/laravel/framework/pull/35218
Will be in next week's release.