Why "test.client" resets container replaced dependencies after request? #49106

Hello, community! I have a question related to testing. I do remember times, when I could set some mock in container like that:

// code inside test suite, which extends WebTestCase 
$client = static::createClient();
$myMock = $this->createMock(SomeInterface::class);
$client->getContainer()->set(SomeInterface::class, $myMock);

And then do several requests, relying on that mock. Then just perform some asserts and check result.

$this->httpClient->request('GET', '/example');
$this->httpClient->request('GET', '/example2');

In my current Symfony version (5.4) I can't do that. For the second request, my mock inside container is just being reset. Eventually my test case fails because of that. And I need setup container service again before each next request. Did somebody had such situation? I haven't found any issues or discussion about that. Maybe there were some info about that also. Can somebody clarify why it is like that? And since which moment that was implemented?