Steps to reproduce the issue

1. Clone a site with J5.0.3

2. In Global Configuration, configure Update Server to "Test" and Minimum Stability to "Release Candidate"
   

3. Ignore warnings in pre-update check

4. Start the Joomla backup

Expected result

Update runs smoothly

Actual result

Update fails with a checksum warning

The log file reveals a wrong download file:

System information (as much as possible)

J5.0.3
PHP 8.3.3
MySQL 8.0.33
joomla_update.php.txt

Additional comments

Sorry: Headline wrong. Should read [5.1.0_Beta2]