I created a couple of CSS classes, where the author can apply those via style systems in a text component. Upon selection of the Style class, the corresponding CSS changes are applied in the author instance. The issue is with respect to publish and preview mode where the appended markup in HTML is getting disappeared.
There is no problem with the clientlibs, it contains the corresponding changes in the publish instance. Only the added markup class name is getting disappeared in publish mode.
My Text resourceSuperType is: core/wcm/components/text/v2/text