Share buttons are replaced by F202 text

My Jetpack share buttons on a few sites are not displaying the correctly e.g. the Twitter, Facebook icons etc but instead are displaying very small texts F202, F204, F210

Any ideas as this has been happening for a good few months. I have disabled all plugins apart from Jetpack but it still happens.

See here for a visual: https://awesomescreenshot.com/0555wy3tb2

Thanks

https://www.ads-software.com/plugins/jetpack/