PDF's turn upside down if you click onto another tab once they are open and go back to them

Summary

After clicking onto a PDF viewing it, going to another tab and back again the PDF is presented upside down.

Steps to reproduce

View a PDF (EG: https://gitlab.com/gitlab-com/www-gitlab-com/blob/master/source/images/press/git-cheat-sheet.pdf)

Click onto another tab

Go back to the PDF Tab

What is the current bug behaviour?

What is the expected correct behaviour?

Output of checks

Gitlab.com