Errors when Advanced Member Search

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Go to /dashboard/users/search and click "Advanced" link in Search text field.
Then the progress bar continues moving and never stops.
Log reports
Exception Occurred: /home/xxx/www/updates/concrete5-8.4.3/concrete/src/Search/Column/AttributeKeyColumn.php:16 Call to a member function getAttributeKeyHandle() on null (0)

I remember it has worked about a few month ago.
Any ideas?

concrete5 8.4.3
PHP 7.2.13