Steps to reproduce the issue

administrator
An error has occurred.
0 array_replace(): Argument #2 must be of type array, int given

Expected result

Line #5 is the "smoking gun":
#5 Joomla\CMS\Plugin\CMSPlugin->loadLanguage() JROOT/plugins/system/stats/src/Extension/Stats.php:126
The System - Statistics plugin (a core Joomla plugin used to collect anonymous usage data).
The Location: /plugins/system/stats/
The Cause: This plugin has a bug in Joomla 6. When it tries to load its language file during site initialization, it is passing incorrect data types that modern PHP does not accept.

Actual result

Disabled
plugins/system/stats/
Admin works.

System information (as much as possible)

Joomla! Version | Joomla! 6.0.0 Stable [ Kuimarisha ] 14-October-2025 16:00 UTC
PHP Version 8.4.14

Additional comments