infection: All mutants marked as not detected when using Composer files autoload option

<?xml version="1.0"?>
<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd"
        backupGlobals="true"
        backupStaticAttributes="false"
        bootstrap="vendor/autoload.php"
        executionOrder="random"
        resolveDependencies="true">

   <coverage includeUncoveredFiles="false">
   <include>
     <directory suffix=".php">./src</directory>
   </include>
 </coverage>

 <testsuites>
   <testsuite name="Unit test">
     <directory>./tests</directory>
   </testsuite>
 </testsuites>

</phpunit>

{
   "$schema": "vendor/infection/infection/resources/schema.json",
   "testFramework":"phpunit",
   "source": {
       "directories": [
           "src"
       ]
   },
   "logs": {
       "text": "infection.log",
       "summary": "summary.log",
       "perMutator": "per-mutator.md"
   },
   "mutators": {
       "@default": true
   },
   "phpUnit": {
       "customPath": "./vendor/bin/phpunit"
   },
   "testFrameworkOptions": "",
   "initialTestsPhpOptions": "-d xdebug.mode=coverage"
}

<?php
class ExpenseReportTest extends TestCase
{
    public function testExpenseReport(): void {

        if(getenv("INFECTION") === 1) {
            $this->assertTrue(false);
        }
   }
}

./vendor/bin/infection --debug

   ____      ____          __  _
  /  _/___  / __/__  _____/ /_(_)___  ____
  / // __ \/ /_/ _ \/ ___/ __/ / __ \/ __ \
_/ // / / / __/  __/ /__/ /_/ / /_/ / / / /
/___/_/ /_/_/  \___/\___/\__/_/\____/_/ /_/

Infection - PHP Mutation Testing Framework version 0.25.1@854bc7f4106252539ebfdf8f29fd4856e7d9ea4c


Running initial test suite...

PHPUnit version: 9.5.9

   9 [============================] < 1 sec
PHPUnit 9.5.9 by Sebastian Bergmann and contributors.

Random Seed:   1631737940

.                                                                   1 / 1 (100%)

Time: 00:00.063, Memory: 14.00 MB

OK (1 test, 1 assertion)

Generating code coverage report in PHPUnit XML format ... done [00:00.008]



Generate mutants...

Processing source code files: 1/1
.: killed, M: escaped, U: uncovered, E: fatal error, X: syntax error, T: timed out, S: skipped

MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM            (41 / 41)

41 mutations were generated:
      0 mutants were killed
      0 mutants were not covered by tests
     41 covered mutants were not detected
      0 errors were encountered
      0 syntax errors were encountered
      0 time outs were encountered
      0 mutants required more time than configured

Metrics:
        Mutation Score Indicator (MSI): 0%
        Mutation Code Coverage: 100%
        Covered Code MSI: 0%

Please note that some mutants will inevitably be harmless (i.e. false positives).

Time: 2s. Memory: 18.00MB