No output on Travis CI for system tests

Hello everyone, I have some weird behavior on a Rails 6.0.4 application when running system tests: when running rails test:system on my machine I correctly see which error is failing, but in Travis I only see the following, without any hint of which error failed:

Puma starting in single mode...
* Version 4.3.8 (ruby 2.6.6-p146), codename: Mysterious Traveller
* Min threads: 0, max threads: 4
* Environment: test
* Listening on tcp://127.0.0.1:34339
Use Ctrl-C to stop
The command "bundle exec rails test:system" exited with 1.

The only thing that pops on my mind is the parallelization, but I tried with and without the parallelize statement in test_helper.rb and it didn’t change much, unfortunately.

Any tips on how to troubleshoot this?