Shot in the dark here, but could it be you're hitting an interactive test that is expecting user input? If so and if it's triggered by the ExtUtils::MakeMaker prompt() sub, you could try setting the PERL_MM_USE_DEFAULT environment variable to TRUE so that it'll bypass the test by selecting the default option.

This happened to me in the past, I don't recall actually seeing the prompt for input (maybe a flush() thing?), just stopping mid-test, and it hangs there until input or until the CI/CD hits its default timeout.

Good luck!