Class attr are getting removed on save in fragments

When I tried to edit a fragment text and save a fragment, class attr got removed.

Enonic version: 6.15.6
OS: 10.14.3 (MAC OS)

When you say edit fragment text, do you mean text component inside a fragment? Which HTML element has the class attribute that gets removed on save?

Yes. I mean the text component inside the fragment. The span class inside the h2 tag gets removed on save.

This issue is fixed in Content Studio for XP7. We are not planning the fix for earlier versions, unfortunately.