TypeError: Argument 1 passed to Drupal\views_migration\Plugin\migrate\views\SourceHandlerInfoProvider::getFieldConfig() must be of the type string, null given

Steps to reproduce

During a complete D7->D9 drush based migration, this error arises:

[error] TypeError: Argument 1 passed to Drupal\views_migration\Plugin\migrate\views\SourceHandlerInfoProvider::getFieldConfig() must be of the type string, null given, called in \web\modules\contrib\views_migration\src\Plugin\migrate\views\SourceHandlerEntityFieldInfoProvider.php on line 55 in Drupal\views_migration\Plugin\migrate\views\SourceHandlerInfoProvider->getFieldConfig() (line 243 of \web\modules\contrib\views_migration\src\Plugin\migrate\views\SourceHandlerInfoProvider.php) #0 \web\modules\contrib\views_migration\src\Plugin\migrate\views\SourceHandlerEntityFieldInfoProvider.php(55): Drupal\views_migration\Plugin\migrate\views\SourceHandlerInfoProvider->getFieldConfig(NULL, '')