[Bug]: Overriding parent tests gives TestCaseAlreadyInUse

[riabiy]

What Happened

Hi. I can be missing something and I believe it's a bug, nevertheless.
Any attempt to override any parent test class gives me TestCaseAlreadyInUse.

Same thing happens both for pest()->extend(SpecificTestCase::class) in the test file and in the Pest.php file.

How to Reproduce

//Pest.php

pest()->extend(DuskTestCase::class)->in('Browser');
//can be in the Specific/AnyTest.php or in the Pest.php, both give same result
pest()->extend(SpecificDuskTestCase::class)->in('Browser/Tests/Specific'); 

Sample Repository

No response

Pest Version

3.4.1

PHP Version

8.3.7

Operation System

macOS

Notes

If this is the desired behaviour, what is the recommended way to override parent class for very-very 1-time niche cases?
In PHPUnit it's just vanilla PHP.
Creating a folder with "PestCanNotOverridePlaceHere" is a bit meh and not Laravelish enough, IMHO.

[riabiy]

Could be a duplicate of #1109 and related to #765.