For bug #13718, the page layout is broken due a long sequence of characters without white spacing between them. .bz_comment_text { word-break: break-all; } works for me.
Pasi Lallinaho referenced this bugreport in commit 6b2dd30465d060fb70743c7a4f9699c6366cec82 Fix issues with word wrapping and too long lines in Bugzilla (Bug #13880) https://git.xfce.org/www/www.xfce.org/commit?id=6b2dd30465d060fb70743c7a4f9699c6366cec82
It seems word-break: break-all wasn't a good idea after all (no rhyme intended). See this comment: https://bugzilla.xfce.org/show_bug.cgi?id=7652#c2 broken words at line ends.
Pasi Lallinaho referenced this bugreport in commit d83316286e5fc6d8477fb9cbd7ac5ecee36b6d2f Another attempt to fix text wrapping and layout for Bugzilla comments (Bug: #13880) https://git.xfce.org/www/www.xfce.org/commit?id=d83316286e5fc6d8477fb9cbd7ac5ecee36b6d2f
Another attempt (hopefully a bit better one) to fix this one pushed to the main branch, should be in production within an hour.