RTE plugin Adding Icons in the styles using inline and full screen editing is not working properly

I want to add font-awesome and Ionicon classes in the styles tab of the rich text editor. For now, I have added corresponding classes in the styles tab and it is rendering properly in the pages.

There are certain scenarios where the author only adds the icon in the rich text without any other content.

In such cases, when authoring through dialogs, I am able to select a class in styles, it is saving and rendering in the pages properly.

When I author through full-screen editing of the in-place editing, the icons are appearing and if I minimize the full screen to inline, it is present and when I try to save it, it doesn't save and the content becomes empty. 

Note: This happens when I add only the icons without any other content from the full-screen mode.

Steps to reproduce:

1)Add the icon in full screen.

2) Minimize to inplace:

3)Saving the changes

See in the end, the content becomes empty and so, the placeholder appears.

Any suggestions to resolve the issue?