Job logs are no longer displayed properly

Summary

Since GitLab 12.? (logs view update), job logs are no longer displayed properly, whereas raw logs contain all the data.

Steps to reproduce

This output is generated by the Symfony framework: https://symfony.com/doc/current/components/process.html#usage image

What is the current bug behavior?

Some of the logs content is missing.

What is the expected correct behavior?

That the display makes good use of all the raw content.

Relevant logs and/or screenshots

Example n°1:

image image

Example n°2:

image image

Output of checks

(If you are reporting a bug on GitLab.com, write: This bug happens on GitLab.com)

Results of GitLab environment info

Expand for output related to GitLab environment info 
(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:env:info)


(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production)

Results of GitLab application Check

Expand for output related to the GitLab application check 
(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:check SANITIZE=true)


(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true)


(we will only investigate if the tests are passing)

Possible fixes

No idea. JS bug?

Edited by tnucera