Steps to reproduce the issue

Select more than one user, click on batch process and move them into another user group

Expected result

Users moved

Actual result

0 Joomla\Database\DatabaseQuery::whereIn(): Argument #2 ($keyValues) must be of type array, null given, called in /administrator/components/com_users/src/Model/UserModel.php on line 774

System information (as much as possible)

PHP Version 8.0.27 Linux info 3.0 #1337 SMP Tue Jan 01 00:00:00 CEST 2000 all GNU/Linux
hoster: Ionos
Joomla 4.2.6
Database structure is up to date
Joomla Core files have been reinstalled