comment in issue history shows up with inline scrollbar in Firefox

Summary

Comment https://gitlab.com/gitlab-org/gitlab-ce/issues/27436#note_22349966 shows a inline scrollbar when viewing with Firefox on Windows:

This does not happen wit Chrome.

Steps to reproduce

(How one can reproduce the issue - this is very important)

Expected behavior

No scrollbar

Actual behavior

Scrollbar

Relevant logs and/or screenshots

see above

Output of checks

This bug happens on GitLab.com