Migration getting stuck at post processing leftover

[thomashellmann]

Preconditions

1. Magento 1.9.4.5
2. Magento 2.4.5 MySQL 8.0.29, PHP 8.1.10
3. several modules installed

Steps to reproduce

1. install Magento 2.4.5 with data-migration-tool 2.4.5
2. run bin/magento migrate:settings [...]/magento2/vendor/magento/data-migration-tool/etc/opensource-to-opensource/1.9.4.5/config.xml without errors
3. run bin/magento migrate:data [...]/magento2/vendor/magento/data-migration-tool/etc/opensource-to-opensource/1.9.4.5/config.xml
4. At post processing step 80% getting error: 'Argument#1 must be of type array, null given'

Expected result

1. Expected succesful migration step post processing after all other steps run without errors

Actual result

Stack Trace
[2022-09-23T19:57:52.770580+00:00][INFO][mode: data][stage: data migration][step: PostProcessing Step]: started
80% [======================>-----] Remaining Time: < 1 secarray_merge(): Argument #1 must be of type array, null given#0 [...]/magento2/vendor/magento/data-migration-tool/src/Migration/Step/PostProcessing/Data/DeletedRecordsCounter.php(93): array_merge()
#1 [...]/magento2/vendor/magento/data-migration-tool/src/Migration/Step/PostProcessing/Data.php(110): Migration\Step\PostProcessing\Data\DeletedRecordsCounter->saveChanged()
#2 [...]/magento2/vendor/magento/data-migration-tool/src/Migration/Mode/AbstractMode.php(82): Migration\Step\PostProcessing\Data->perform()
#3 [...]/magento2/vendor/magento/data-migration-tool/src/Migration/Mode/Data.php(124): Migration\Mode\AbstractMode->runStage()
#4 [...]/magento2/vendor/magento/data-migration-tool/src/Migration/Mode/Data.php(69): Migration\Mode\Data->runData()
#5 [...]/magento2/vendor/magento/data-migration-tool/src/Migration/Console/MigrateDataCommand.php(59): Migration\Mode\Data->run()
#6 [...]/magento2/vendor/symfony/console/Command/Command.php(255): Migration\Console\MigrateDataCommand->execute()
#7 [...]/magento2/vendor/magento/framework/Interception/Interceptor.php(58): Symfony\Component\Console\Command\Command->run()
#8 [...]/magento2/vendor/magento/framework/Interception/Interceptor.php(138): Migration\Console\MigrateDataCommand\Interceptor->___callParent()
#9 [...]/magento2/vendor/magento/framework/Interception/Interceptor.php(153): Migration\Console\MigrateDataCommand\Interceptor->Magento\Framework\Interception{closure}()
#10 [...]/magento2/generated/code/Migration/Console/MigrateDataCommand/Interceptor.php(77): Migration\Console\MigrateDataCommand\Interceptor->___callPlugins()
#11 [...]/magento2/vendor/symfony/console/Application.php(1009): Migration\Console\MigrateDataCommand\Interceptor->run()
#12 [...]/magento2/vendor/symfony/console/Application.php(273): Symfony\Component\Console\Application->doRunCommand()
#13 [...]/magento2/vendor/magento/framework/Console/Cli.php(116): Symfony\Component\Console\Application->doRun()
#14 [...]/magento2/vendor/symfony/console/Application.php(149): Magento\Framework\Console\Cli->doRun()
#15 [...]/magento2/bin/magento(23): Symfony\Component\Console\Application->run()
#16 {main}

Additional notes

Tried to find information about this error on google without success. Hope, anyone can help me understanding this error and necessary steps to avoid it.

[m2-assistant]

Hi @thomashellmann. Thank you for your report.
To speed up processing of this issue, make sure that you provided sufficient information.

Add a comment to assign the issue: @magento I am working on this

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[thomashellmann]

I tried to figure out, if it could have been one of the attributes migrated. So I updated my XML files, to not migrate obsolete attributes. But without success, I still got the same error.