Steps to reproduce the issue

• Joomla 5 nightly build (25.8.23)
• with Blog Sample Data installed
• php 8.1.12
• MariaDB 10.4.27
• no 3rd components installed

with a search term and a start and end date (Assuming typography is required, and beginning date before Saturday, 26 August 2023, and ending date before Tuesday, 29 August 2023, the following 2 results were found.) I get this error message:
Deprecated: mb_strtolower(): Passing null to parameter #1 ($string) of type string is deprecated in C:\xampp\htdocs\joomla5\libraries\vendor\joomla\string\src\phputf8\mbstring\core.php on line 120

Expected result

Actual result

System information (as much as possible)

Additional comments