Internet Explorer merge request and todo icon not showing

Summary

A customer is running into problems with Internet Explorer (v11.0.9600.19301 and v11.472.17134.0). They are running GitLab instance v11.10.1

err3

It seems that icons are not displayed

err1

err4

Related Zendesk ticket: https://gitlab.zendesk.com/agent/tickets/120516 (internal)

Edited by Ronald van Zon