The issue seems related to the CSS ::first-letter pseudo selector Selector. It is not supported in all the browsers version.
So please inspect your style sheets.
More information about that selector could be found here
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Sitefinity CMS Ideas&Feedback Portal
and vote to affect the priority of the items