Hi, We have the same problem here, but this time for font-awesome (which is being used in our LOB webapp and on some other websites too).
Without installing the font beforehand when we open the website it does not render the font (not being able to download it, eventhough the gpo for Internet Explorer is configured to allow font downloads). When I install the font manually it works until I log off and log on again. Immediately after logon it may stll work, but after some time it stops working.
After I give deny on apply group policy to myself on the UEM gpo (which only contains the UEM settings) the font-awesome is always correctly displayed. When I turn on the GPO again it stops working.
This is a real problem for us as the only solution would be to stop using UEM.
You can test it on Font Awesome Icons with internet explorer 11 on Windows 10 Enterprise 1607 in a Windows 2012 R2 domain with UEM 9.2 via group policy extensions.
Other browsers do not have this problem.
Kind regards,
Jos Rossiau